# Light fast arrows vs. heavy for hunting



## Joe Ryan (Jun 8, 2014)

I've got 2 sets of arrows. CX Heritage 150 @ 28.75" with 100gr inserts and 125gr BH's that weigh 535grs, and a set of CX Blue streaks @ 29.24" with 50gr inserts and 125gr BH's that weigh 383grs. Both sets have been bare shaft tested, and are exactly the proper spine for my set-up. I use an OMP Mountaineer, 62" and 50# @ my 26.75" DL. I don't have a chronograph, so I can't calculate KE, but the lighter arrow is over 30fps faster. My skill level limits me to shots inside 30yds ( can group inside an 8" pie plate at 33 yds ). My question is, which set is better suited for deer and possibly black bear hunting ? My BH's are cut on contact 2 blade Magnus Stingers with a bleeder blade. Suggestions welcome.


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## Bill 2311 (Jun 24, 2005)

Don't worry about KE. Calculate momentum. It is a better guide for arrows. 
I shot all carbons during summer and up close to season. They weighed 385 grains. I opted for a heavier shaft and went to an aluminum 2016 that weighs 480 grains. For me it was a good balance between trajectory (20 and under), point of hold, and momentum for penetration. I shoot a two blade Zwickey.
Since you asked, either is good for deer, but for a bear I would go with the heavy shaft.


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## kegan (Aug 28, 2006)

Use whatever you're more accurate with and is better tuned.


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## SonnyJ (Sep 2, 2012)

50# draw....either setup should be able to give you a pass thru as long as you have sharp blades.


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## Viper1 (Aug 21, 2003)

Joe - 

Do a google search.
Every new shooter inundated with various magazine and internet theories and ads asks the same thing.

The simple fact is there are as many successful hunters with light/fast(er) as there are heavy/slow(er) arrows - and everything in between.
Like Kegan said, use whatever shoots best.

Viper1 out.


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## Windrover (Jan 6, 2012)

For deer either will be fine. For bear I would stick to the heavy arrow. Most bear shots are setups so range will not be a problem. The late John Wooters used to point out that when selecting a weapon for black bear you need to think about what is the biggest bear that you could see in the area you will hunt. Consider this article www.cbc.ca/news/canada/thunder-bay/345kg-bear-shot-in-longlac-rivals-ontario-record-1.2777804, yes that's 760 lbs. Take the big arrow for one like that.


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## 2413gary (Apr 10, 2008)

I miss OSB


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## Beendare (Jan 31, 2006)

I style my hunting arrows for a less than perfect scenario and opt for the better penetration of the heavier arrows....plus the heavier arrow quiets down your bow which is an advntage in a hunting situation- less animal movement on the shoot


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## Easykeeper (Jan 2, 2003)

Aside from what would work for hunting, your lighter arrow is flirting with what might be too light for the long term durability of your bow. I don't know about the OMP Mountaineer, but some manufacturers and bowyers recommend you stay above 8 grains per pound of draw weight. Your lighter arrow are in the 7.66 grains per pound range. It may or may not be a problem, but I'd be surprised if your heavier arrows don't make the bow quieter. The reduced noise is less energy being dissipated by the bow. 

In general the heavier the arrow the more efficient the energy transfer from the bow, but obviously that needs to be balanced with the trade off in trajectory.

What's noisy to one is quiet to another so that's another subjective value.

My setup is pretty similar to you with the heavier arrows, 50# bow and an arrow around 10 grains per pound. Shoots nice and quiet and at bowhunting ranges the cost in trajectory is not really noticeable to me.


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## Joe Ryan (Jun 8, 2014)

Im wondering if ther is a way to calculate arrow speed without a chronograph ? My bow is 51# @ my 26.75" draw using 535gr arrows.


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## kegan (Aug 28, 2006)

Not accurately. What are you hunting specifically?


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## rattus58 (Jul 9, 2007)

Joe Ryan said:


> Im wondering if ther is a way to calculate arrow speed without a chronograph ? My bow is 51# @ my 26.75" draw using 535gr arrows.


I don't know, but your total arrow weights are ideal for hunting. A little lighter might give you a little better trajectory, but I'd not personally go much below 450 with your setup, but the lighter you do go, the more I'd look to keeping the center of gravity forward as well. How your arrow flies and your control of it is the most important, but if you want the most performance from your arrow for difficult shots, cg matters... also called FOC... forward of center.

Aloha...


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## ozarksbuckslaye (Jul 24, 2008)

An arrows kinetic energy in foot pounds is a reliable and accurate measurement of its ability to do work. Ballistic calculations work exactly the same for arrows as they do for bullets. The formula for KE is simple and easy, velocity squared multiplied by arrow weight in grains divided by 450,240.

What gun would make more sense to deer hunt with a 4570 govt. or a 7mm Ultra Mag?

4570 405gr bullet 1,330 fps 1,590 fps ke
7mm 140gr bullet 3,700 fps 4,256 fps ke

Both kill deer but one shoots faster and has flatter trajectory and packs more punch. Arrows kill by hemorrhage basically and not so much from trauma caused by shock. The impact energy of arrows are in the same ballpark as a .22 caliber long rifle. The energy difference between a heavy arrow vs a light arrow is probably like 5 pounds at best. Sacrificing a flatter trajectory curve and quicker flight time for a couple of measly pounds of KE isn't a very smart trade off especially since most people are shooting enough ke to zip an arrow through the rib cages of 3 deer if they were all standing just right.


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> An arrows kinetic energy in foot pounds is its ability to do work. Ballistic calculations work exactly the same for arrows as they do for bullets. The formula for ke is easy, velocity squared multiplied by arrow weight in grains divided by 450,240.
> 
> What gun would make more sense to deer hunt with a 4570 govt. or a 7mm Ultra Mag?
> 
> ...


Kinetic energy is work... that can be stopped rapidly with light bullets. Momentum, as was mentioned earlier, is what happens when the bullets or arrows get there. Going through a deer is not a good test of what is best. Trying to shoot lengthwise through a deer or elk on the other hand tests Kinetic energy, because a light bullet or arrow has little carry through momentum once the going gets rough.

Light arrows are great, but not the best for penetration by any means. Responsible hunters don't need the benefits of heavy arrows when everything works right. The rest of us like arrows that work when they don't... and that is an 8 to 12 grain per pound of draw weight... :laugh:

Aloha...


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> Kinetic energy is work... that can be stopped rapidly with light bullets. Momentum, as was mentioned earlier, is what happens when the bullets or arrows get there. Going through a deer is not a good test of what is best. Trying to shoot lengthwise through a deer or elk on the other hand tests Kinetic energy, because a light bullet or arrow has little carry through momentum once the going gets rough.
> 
> Light arrows are great, but not the best for penetration by any means. Responsible hunters don't need the benefits of heavy arrows when everything works right. The rest of us like arrows that work when they don't... and that is an 8 to 12 grain per pound of draw weight... :laugh:
> 
> Aloha...


I'm glad you shared that. Guy likes to see ****'s naked. That don't help me.

See I can also give an insulting response to someones intelligence. Some may buy what you're selling but experience has taught me the truth.


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> I'm glad you shared that. Guy likes to see ****'s naked. That don't help me.
> 
> See I can also give an insulting response to someones intelligence. Some may buy what you're selling but experience has taught me the truth.


You probably wouldn't know the truth if it buried you like an avalanche. From your response, it is obvious that intelligence wise, you deserve a refund. The fact that you like to see naked guys only points out that you you have your arrows mixed up.


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> You probably wouldn't know the truth if it buried you like an avalanche. From your response, it is obvious that intelligence wise, you deserve a refund. The fact that you like to see naked guys only points out that you you have your arrows mixed up.


:lol3: You've still got everything bass ackwards. I shot a deer that was facing head on in the throat with a 350 gran arrow and it came out its ass. Tell me that never happened. I'm sure you like to think that you know everything about everything but the fact of the matter is that you do not.


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> :lol3: You've still got everything bass ackwards. I shot a deer that was facing head on in the throat with a 350 gran arrow and it came out its ass. Tell me that never happened.


 why would I do that? That's a relatively low interference shot so it's not an unexpected result, and a shot I'm sure you're quite comfortable with.


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> Going through a deer is not a good test of what is best. Trying to shoot lengthwise through a deer or elk on the other hand tests Kinetic energy, because a light bullet or arrow has little carry through momentum once the going gets rough.


I sure wish you would make up your mind. First you say going through a deer is not a good test. Then you say shooting lengthwise through a deer on the other hand is. That didn't make any sense to start with because a deer facing lengthwise is still a deer and I have proven lightweight arrows can shoot clean through one that is facing lengthwise. Sounds to me like you just simply refuse to face the facts.


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## rattus58 (Jul 9, 2007)

Is more of the lengthwise through the deer I was thinking... and breaking the offside shoulder at conclusion.


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## ozarksbuckslaye (Jul 24, 2008)

I'm guessing now you're going to say shooting through one lengthwise isn't a good test either? Haha you kill me!


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> I'm guessing now you're going to say shooting through one lengthwise isn't a good test either? Haha you kill me!


 Can you read?


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## ozarksbuckslaye (Jul 24, 2008)

Allow me to explain to you how this stuff works. Each and every bow is only capable of storing X amount of energy. When the bow is fired most of that stored energy is transferred to the arrow. The arrow sheds a small percentage of that energy during flight at normal hunting distances. The remaining of what is left can be calculated if the distance is known. That calculated amount dictates exactly how much energy will be transferred into whatever it strikes. That's kind of why bow manufacturers put IBO speeds on their bows so people can know what it's capable of doing. Much like how gun manufacturers print bullet grain weight as well as the velocities for different bullets and for different calibers. It ain't rocket surgery. If momentum was a better indicator of performance than kinetic energy then maybe you need to take that up with the experts who design weapons instead of wasting your time on some pee on that doesn't know anything on an internet forum.


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> Allow me to explain to you how this stuff works. Each and every bow is only capable of storing X amount of energy. When the bow is fired most of that stored energy is transferred to the arrow. Some of that energy the arrow sheds during flight. The remaining of what is left can be calculated if the distance is known. That calculated amount dictates exactly how much energy will be transferred into whatever it strikes. That's kind of why bow manufacturers put IBO speeds on their bows so people can know what it's capable of doing. Much like how gun manufacturers print velocities of bullets for different calibers. It ain't rocket surgery.


none of this matters till the arrow or bullet hits something. The energy of a light bullet dissipates at at a phenomenal rate compared to heavier bullets. Light bullets and arrows depend on velocity for energy, a heavy bullet depends on weight to finish the job. Drag matters, and heavy bullets do a better job of overcoming drag and they do a better job of remaining stabilized once in the target. Heavy arrows versus light arrows have the same factors to contend with. 

The advantage of a light arrow is basically trajectory. Once it has has hit the animal, the residual velocity and drag determine penetration.... pretty much period. A heavy arrow or a light arrow with a well forward CG do much better in penetration given the same drag coefficients.


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## ozarksbuckslaye (Jul 24, 2008)

That's all fine and dandy but everything you just said isn't going to resurrect any game that has been taken with lightweight ammo including some elephants that were killed with High Country Speed Pro arrows lol.


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> That's all fine and dandy but everything you just said isn't going to resurrect any game that has been taken with lightweight ammo including some elephants that were killed with High Country Speed Pro arrows lol.


tell me about that? Where was that?


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> tell me about that? Where was that?


Just guessing but I figure it was somewhere in Africa.


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> Can you read?


Apparently not very good. I'm just now realizing I was posting in the traditional section. Oops. Anyhow the same basic rules apply to both unless your name is Dr. Ashby. He has made it clear on numerous occasions that the laws of physics do not particularly apply to him. If sharpbroadhead is still posting then he can tell ya' the same thing I just did. 
:icon_1_lol:


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> Just guessing but I figure it was somewhere in Africa.


In many places in Africa they have minimum standards for hunting heavy game with a bow. 65# of KE is typical in several places that I'm aware.

Here is what you'd need bow wise to hunt heavy plains game.

Efficiency Factors 
Draw Wt	65
grains	415
GPP	6.384615385
speed	266
Bullet Diameter	0.34375
KE	65.18756799
Momentum	0.49013209
momentum_1	4.901320901
Taylor	5.4209375
Eff. Factor	1.003
Mom. Eff.	0.075




Efficiency Factors 
Draw Wt	65
grains	450
GPP	6.923076923
speed	256
Bullet Diameter	0.359375
KE	65.47052947
Momentum	0.511488511
momentum_1	5.114885115
Taylor	5.914285714
Eff. Factor	1.007
Mom. Eff.	0.079

Buffalo and the like require at least 80# draw weight and a 750 grain arrow.


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> Apparently not very good. I'm just now realizing I was posting in the traditional section. Oops. Anyhow the same basic rules apply to both unless your name is Dr. Ashby. He has made it clear on numerous occasions that the laws of physics do not particularly apply to him. If sharpbroadhead is still posting then he can tell ya' the same thing I just did.
> :icon_1_lol:


Sharp Broadhead is no one you should wish to be emulating and the fact that you list him as your idol worship says a lot.


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## Doofy_13 (Jan 2, 2012)

From my personal experience....heavier arrows do penetrate better.


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## Arrowwood (Nov 16, 2010)

Rattus, at least OSB was getting pass-throughs with his light arrows. Didn't you tell the forum that you never had an arrow pass through an animal?


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## rattus58 (Jul 9, 2007)

Arrowwood said:


> Rattus, at least OSB was getting pass-throughs with his light arrows. Didn't you tell the forum that you never had an arrow pass through an animal?


No, I said that I only had one complete pass through where the arrow cleared the animal. If you paid attention to detail, you'd have uncovered that my broadheads always made it through and on several occasions, breaking bone. I've also never lost an animal to archery. So what is your point?


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## Matt_Potter (Apr 13, 2010)

rattus58 said:


> No, I said that I only had one complete pass through where the arrow cleared the animal. If you paid attention to detail, you'd have uncovered that my broadheads always made it through and on several occasions, breaking bone. I've also never lost an animal to archery. So what is your point?


That being the case I'd probably stop holding forth on penetration LOL


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## rattus58 (Jul 9, 2007)

Matt_Potter said:


> That being the case I'd probably stop holding forth on penetration LOL


 Yeah.... I get gas for that from them skinny 250fps arrow chuckers all the time... :laugh: But my 3/8" arrows are slow, draggy, and long... :grin:


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## DDSHOOTER (Aug 22, 2005)

I like to shoot with point on the animal. Jimmy Blackmon has some good video's. Choose the arrow/boardhead you want to hunt with then tune the bow to that arrow for best shot placement. I like to shoot out to 60 yards for compound.
Dan


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## Beendare (Jan 31, 2006)

What really opened my eyes to how effective heavy arrows are was when we did a Australian water buffalo hunt and shot my lighter arrows into a dead buff [440gr, 560 gr] from the same bow I killed the beast with [840gr]

When the 440,560 failed to make it through the rib cage on multiple close shots with the 840 being a complete pass through....... it really drove home how much arrow weight affects penetration


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## BarneySlayer (Feb 28, 2009)

2413gary said:


> I miss OSB


Me too


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## BarneySlayer (Feb 28, 2009)

ozarksbuckslaye said:


> :lol3: You've still got everything bass ackwards. I shot a deer that was facing head on in the throat with a 350 gran arrow and it came out its ass.


I'd like to hear that story


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## Aronnax (Nov 7, 2013)

ozarksbuckslaye said:


> An arrows kinetic energy in foot pounds is a reliable and accurate measurement of its ability to do work.


I really don't want to get into this pissing contest of back and forth straw man arguments and sophisms, but I can't let the above statement go uncorrected.

KE is the ENERGY of an arrow. You are correct. Momentum is the arrow's ability to RETAIN its ENERGY while passing through a given medium.

If you have a lot of KE, but little momentum, the projectile will decelerate more rapidly while passing through a medium of a given density.

If you have the same KE, but a lot of momentum, the projectile will decelerate more slowly (retaining more velocity) while passing through a medium of a given density.

Of course, not that it should need to be mentioned, but seems to be never understood, "WITH ALL ELSE BEING EQUAL".

With archery, heavy arrows always, within practical constraints, ALWAYS, have more KE and Mo. when shout out of a given bow. Velocity goes down, with arrow mass, but efficiency ALWAYS goes up, again, WITHIN REASONABLE PRACTICAL CONSTRAINTS.

The above concept has been proven scientifically, with empirical, objective data. Anyone with some time, a stack of arrows, a chronograph, and a lick if intelligence and a basic knowledge of the scientific process can reproduce the results.

Anecdotal pass through "data" is pseudo data. For data to be worth anything, it needs to be repeatable. An animal carcass is not a homogenous substance. Each individual animal in a group can also vary. All a pass through proves is that for that specific shot on that specific animal, you had sufficient KE and Mo. to overcome the drag on that arrow in that medium and exit the opposite side. It is completely irrelevant in any scientific discussion. For actual animal shots to have any merit, you would need a statistical population large enough to average out the uncontrolled variables. In the case of actual hunting situations, the number of uncontrolled variables is almost impossible to count. You would need a HUGE population sample, with all the data that could be collected, to be collected as accurately as possible. A statistical study with just one sample has a margin of error approaching 100%.

But, judging past history of how these kinds of threads and arguments go, you will completely disregard science, and physics, and rather rely on fairy-tales and pixie dust, unicorns, and pots of gold at the ends of rainbows, on which to base your beliefs.

BM


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## kegan (Aug 28, 2006)

ozarksbuckslaye said:


> Apparently not very good. I'm just now realizing I was posting in the traditional section. Oops. Anyhow the same basic rules apply to both unless your name is Dr. Ashby. He has made it clear on numerous occasions that the laws of physics do not particularly apply to him. If sharpbroadhead is still posting then he can tell ya' the same thing I just did.
> :icon_1_lol:


Traditional bows have a few draw backs that don't allow them to be able to effectively make the most of such a wide range of arrow weights. For example, let's take a 50# traditional bow. With a heavy arrow, say 600 gr, you will be getting around 40 ft-lbs of KE. If you shoot a 250 gr arrow from the same bow though, that number drops down to around 27 ft-lbs of KE. All coming down to the design.

Many of the better designed ILF limbs have very good efficiency with lower weight arrows, and will usually see a far smaller loss (usually only a few pounds going from say 12 gpp to 7 gpp). However, not all bows are designed that way. Many wood-and-fiberglass recurves and longbows or a more "traditional" design will have the issue my first example has, and that's a massive drop off in efficiency.

For deer, turkey, and other smaller big game it's a non issue. You'd be able to tell when you start losing serious energy because the bow would become very loud and uncomfortable. Provided you're within the warranty limits finding the best arrow is just a matter of tuning and seeing what you like best. Deer aren't armor plated, last time I checked.


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## patrick2cents (Jan 26, 2014)

Eh, just go heavy enough to kill it and light enough to get the range you want... it isn't that hard ;-)


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## Yewselfbow (Jan 28, 2006)

If weight = 20 and speed = 10 then the force calculation would be 20 x 10 = 200 ... but
If weight = 10 and speed = 20 then the force calculation would be 10 x 20 = 200 .... so
does that mean that a heavy arrow going slow is the same as a light arrow going fast? .... just askin'


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## Cris Anderson (Oct 22, 2014)

Yewselfbow said:


> If weight = 20 and speed = 10 then the force calculation would be 20 x 10 = 200 ... but
> If weight = 10 and speed = 20 then the force calculation would be 10 x 20 = 200 .... so
> does that mean that a heavy arrow going slow is the same as a light arrow going fast? .... just askin'


Until it hits an object of whatever density. Then it becomes about how capable of carrying its speed an object is. That's determined by momentum.

I have no dog in this fight...I'm just learning. That said it makes total sense that an object that is 'harder' to stop...i.e an object with more momentum...would penetrate farther through whatever material it encounters. As a short draw guy my problem isn't with the logic, it's with finding the right balance.


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## Aronnax (Nov 7, 2013)

Yewselfbow said:


> If weight = 20 and speed = 10 then the force calculation would be 20 x 10 = 200 ... but
> If weight = 10 and speed = 20 then the force calculation would be 10 x 20 = 200 .... so
> does that mean that a heavy arrow going slow is the same as a light arrow going fast? .... just askin'


Uh- no, not exactly. No need to keep repeating work that has already been completed on this subject. Also to note, it's not arrow "weight" but "mass" that is needed for the calculations. 

http://archeryreport.com/2009/11/arrow-kinetic-energy-momentum-archer/

http://archeryreport.com/2012/01/kinetic-energy-momentum-arrows-simplified-approach/

Compound bows generally generate 2 - 3x, or even more, in some cases, KE than an average hunting trad bow. That is why they can tolerate very light gpp arrows (5 - 6) and throw away a lot more to efficiency losses, and lower Mo. numbers, and still have plenty of energy to spare. With trad gear, you are walking a lot closer to the "just enough" line, which is why you aren't going to see a lot of longbow hunters with 2" mechanicals and 350gr arrows.

BM


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## eclark53520 (Sep 11, 2012)

Aronnax said:


> I really don't want to get into this pissing contest of back and forth straw man arguments and sophisms, but I can't let the above statement go uncorrected.
> 
> KE is the ENERGY of an arrow. You are correct. Momentum is the arrow's ability to RETAIN its ENERGY while passing through a given medium.
> 
> ...


Thank you for saving me a lot of typing....

Some people just refuse to stand back and realize they don't know everything.


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## kegan (Aug 28, 2006)

I think for most of us, hitting it in the right spot means more than how far the arrow goes through. 

Use whatever helps you keep it in the vitals best.


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## Windrover (Jan 6, 2012)

Aronnax said:


> I really don't want to get into this pissing contest of back and forth straw man arguments and sophisms, but I can't let the above statement go uncorrected.
> 
> KE is the ENERGY of an arrow. You are correct. Momentum is the arrow's ability to RETAIN its ENERGY while passing through a given medium.
> 
> ...


I also hate to "weigh in" but who has the large sample ? Dr. Ashby.


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## Aronnax (Nov 7, 2013)

Joe Ryan said:


> Im wondering if ther is a way to calculate arrow speed without a chronograph ? My bow is 51# @ my 26.75" draw using 535gr arrows.


Like Kegan said, not accurately. You would need to make a lot of assumptions.

If KE=w*v^2/450800 then V = sqrt(KE *450800 / w) where KE is arrow KE and, w is arrow weight in grains.

If arrow KE is the Bow's stored energy * efficiency you can substitute that in the above equation-

V = sqrt(SE * efficiency * 450800 / w)

SE is a function of your bow's force draw curve, and there's really no way to know it without actually measuring your bow's force draw curve and calculating it. Again, you can make assumptions based on similar bows that have published data available, which can be anywere form .75 ft/lbs per lb draw weight, up to .95. A short draw length, and high brace heights (short power stroke) are very detrimental to the bow's stored energy numbers.

So, pretend you bow stores 40KE of potential energy (.8ke's per lb draw force), is is 80% efficient, a 535gr arrow would travel 164fps.

BM


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## rattus58 (Jul 9, 2007)

Windrover said:


> I also hate to "weigh in" but who has the large sample ? Dr. Ashby.


There are millions, probably, of old retired hunters from the 50's, 60's and 70's that can supply you with tons of anecdotal data of the 8-12 gpp in hunting American game... and many of the notables suggested 10 as a compromise. :laugh:


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## rattus58 (Jul 9, 2007)

Aronnax said:


> Like Kegan said, not accurately. You would need to make a lot of assumptions.
> 
> If KE=w*v^2/450800 then V = sqrt(KE *450800 / w) where KE is arrow KE and, w is arrow weight in grains.
> 
> ...


 Much easier this way... point and click... :laugh:

We seem to have some disagreement on arrow weights... wonder why that would be?

grains	535
speed	164
Bullet Diameter	0.359375
*KE	31.94441114*
Momentum	0.38956599
momentum_1	3.895659896
Taylor	4.504508929



Efficiency Factors Draw Wt	50
grains	680
GPP	13.6
speed	164
Bullet Diameter	0.34375
KE	40.6022422
Momentum	0.495149295
momentum_1	4.951492951
Taylor	5.476428571
Eff. Factor	0.812
Mom. Eff.	0.099


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## MGF (Oct 27, 2012)

kegan said:


> I think for most of us, hitting it in the right spot means more than how far the arrow goes through.
> 
> Use whatever helps you keep it in the vitals best.


I'm going with Kegans answer.

It could be that you just need more bow to hunt elephants. LOL


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## Aronnax (Nov 7, 2013)

rattus58 said:


> We seem to have some disagreement on arrow weights... wonder why that would be?


Not sure what you mean, arrow weight is a constant as defined by the OP, along with draw weight.

The red highlight is your KE, which is ARROW KE. I started out with bow STORED ENERGY. 40ft/lbs SE * 80% efficiency = 32 ft/lbs ARROW ENERGY. Any discrepancy beyond that is due to rounding error. Some people define the acceleration of gravity as 32.2ft/s^2, some more anal types 32.17ft/s^2, or 32.174ft/s^2. In terms of making really, really, rough estimations, I tend to round off a lot of decimal places.

BM


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## rattus58 (Jul 9, 2007)

Aronnax said:


> Not sure what you mean, arrow weight is a constant as defined by the OP, along with draw weight.
> 
> The red highlight is your KE, which is ARROW KE. I started out with bow STORED ENERGY. 40ft/lbs SE * 80% efficiency = 32 ft/lbs ARROW ENERGY. Any discrepancy beyond that is due to rounding error. Some people define the acceleration of gravity as 32.2ft/s^2, some more anal types 32.17ft/s^2, or 32.174ft/s^2. In terms of making really, really, rough estimations, I tend to round off a lot of decimal places.
> 
> BM


Got it..... I missed the assumption part of stored energy.... :grin: Point and click is still easier for me.... :laugh: Good job!


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## secretagentmann (Jul 6, 2012)

55# Gamemaster 2. 29" draw. Gold tip blems 400s 31" 100gr insert 200gr tip. 
Total weight just under 600gr.
Clocks 182fps. Nice and quiet.
Seems in my experience, heavier is quieter


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## rattus58 (Jul 9, 2007)

secretagentmann said:


> 55# Gamemaster 2. 29" draw. Gold tip blems 400s 31" 100gr insert 200gr tip.
> Total weight just under 600gr.
> Clocks 182fps. Nice and quiet.
> Seems in my experience, heavier is quieter


tis in deed... :grin:


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## Roger Savor Sr (Feb 16, 2014)

Lots of theory here based on conjecture and backed by hearsay......That's not a good thing by the way. My actual experience with 'light' arrows is that 375gr'ers will sail effortlessly through very large PA Whitetails. I'd be more concerned with how well your bow is tuned and if your consistent enough in hitting the mark. Kinetic Energy is a scalar movement which has no direction and lacks force. What some think it has to do with arrow penetration is beyond me. Your arrow will work fine, btw...........and not because I think it will, either, but have been there done that too many times.


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## Matt_Potter (Apr 13, 2010)

^^^^^bingo we have a winner ^^^^


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## Windrover (Jan 6, 2012)

rattus58 said:


> There are millions, probably, of old retired hunters from the 50's, 60's and 70's that can supply you with tons of anecdotal data of the 8-12 gpp in hunting American game... and many of the notables suggested 10 as a compromise. :laugh:


I agree with you and Aronnax. There are many opinions about arrows meeting game but only Dr Ashby has a significant data record to reach conclusions. When someone else shows data on thousands of shots then I will pay attention. As a moose hunter I would not hunt with less than 10gpp recurve or compound.


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## ozarksbuckslaye (Jul 24, 2008)

Arrowwood said:


> Rattus, at least OSB was getting pass-throughs with his light arrows. Didn't you tell the forum that you never had an arrow pass through an animal?





Matt_Potter said:


> That being the case I'd probably stop holding forth on penetration LOL


:lol3:



BarneySlayer said:


> I'd like to hear that story


There's not much to tell other than what I already said. The deer was facing me and I shot it. The arrow passed cleanly through it from appetite to bunghole.



kegan said:


> Deer aren't armor plated, last time I checked.


You're exactly right. Winner winner chicken dinner. 

This evening I made meat using a bang stick for some summer sausage. The bullet went 6 inches through the center of a white oak about 10 yards in front of the deer. The tree looked like it got struck by lightning lol. 140 grains of lead fragmented into 13 different pieces before hitting the deer. The blood trail was about 6' wide. If people spent half as much time actually hunting as they did worrying about what will or wont kill game effectively then they would already know instead of questioning every little detail about their equipment.


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## Fortyneck (Oct 8, 2010)

Hot, nasty, bad-ass speed. :wink:


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## ozarksbuckslaye (Jul 24, 2008)

:smile:


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> :lol3:
> 
> There's not much to tell other than what I already said. The deer was facing me and I shot it. The arrow passed cleanly through it from appetite to bunghole.
> 
> ...


And you used a bang stick to kill a deer you say? And through a white oak you say.... ???


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> And you used a bang stick to kill a deer you say? And through a white oak you say.... ???


Yup. Pew,pew,pew. :uzi::sign10:

The orange army invasion ended today so tomorrow I'll be a stick n' string hunter again. :thumbs_up


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## weekender21 (Jan 27, 2012)

Lighter arrows will slow faster when they encounter resistance (animal). Momentum (heavier arrow) is the more important factor WRT arrow penetration. However, I think it's a distant second to accurate shot placement. Archers are well suited with arrows in the middle that don't hinder ballistic performance and offer enough momentum for good penetration on a less than perfect hit. We (archery hunters) are very opinionated and certainly don't all agree where that "middle" is. So this is just that, my opinion. 

Ballistically you have too shoot a much lighter arrow to see any real ballistic change inside 50 yards. I was comparing arrows last summer and was surprised with the results. At the time my 60lb bow with a 29" draw was shooting 400 and 448 grain arrows into the exact same spot out to 40 yards. At 50, the heavier arrow was only 2" low. At 80 yards the difference was a more noticeable 18" difference. 

Everyone has to make their own decision but I tend to lean towards slightly heavier arrows and usually end up over 420 grains at 60 pounds and over 450 grains at 70 pounds. From my experience, the heavier arrows penetrate better. It's good insurance when your shot misses the mark a little.


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> Yup. Pew,pew,pew. :uzi::sign10:
> 
> The orange army invasion ended today so tomorrow I'll be a stick n' string hunter again. :thumbs_up


so tell me about your bang stick 0zark.. you say it shot a bullet through a white oak, fragmented in the process and *then the bullet fragments ENTERED the deer* and it left a 6" blood trail... have I got that right?


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> so tell me about your bang stick 0zark.. you say it shot a bullet through a white oak, fragmented in the process and *then the bullet fragments ENTERED the deer* and it left a 6" blood trail... have I got that right?


Yes sir that is correct all except the 6" part. Six feet wide is what I said. The gun is a Remington 700 BDL 7mm Ultra Mag with a 26" barrel. Nosler 140 grain ballistic tips on top of 94 grains of reloader 25 powder. She's a wicked beast.


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## JParanee (Oct 13, 2009)

Did you mean to shoot the 6 foot wide tree


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## Robert Carter (Apr 2, 2014)

Don`t know if this pic will work as I have never posted one here but this is from a 48lb longbow and 525 grain arrow . Bow was shooting 162fps. Not bad penetration for a 3 blade head. RC


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## Robert Carter (Apr 2, 2014)

With a trad bow shooting the weight the average fella hunts with on deer it really don`t matter that much in my opinion on arrow weight to a point. If you hit shoulder your gonna be in trouble no matter if your heavy or light. It don`t take much to shoot through one anywhere else. Personally I would not go below 475 grains for deer with wide two blades or narrow three blades. With say a snuffer I would up that a bit to maybe 550. I`ve killed a few animals with longbows around 47-50 pounds at 27" with arrows in the 550 range using big Simmons,Magnus I heads and snuffers. The broadhead came out the other side on most all of them.
sharp means more than a few grains of arrow weight and shot placement is the deciding factor. its not as complicated as we make it.RC


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## ozarksbuckslaye (Jul 24, 2008)

JParanee said:


> Did you mean to shoot the 6 foot wide tree


Lol nope. That was indeed operator error. I was trying to shoot it through the shoulders because that tree was in the way of me hitting where I wanted to. I hit it right behind the shoulder by mistake. It was about a 150 yard shot through the timber and I was shooting offhand so the possibility of that happening did cross my mind before the shot. Oops. :smile:


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## Robert Carter (Apr 2, 2014)




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## ThomasC4 (Nov 18, 2014)

I personally like the lightest arrows my bow can safely handle. 

The speed of the arrow creates KE also. 

A 380grain arrow flying at 330 fps has 91 ft lbs of KE
A 530 grain arrow flying at 280 fps has 92 ft lbs of KE
Todays bows can easily achieve this. 

Which is better? 

You cut the deer you don't knock it over. It is totally different than a bullet. Bullets need to create damage and trauma due to the shockwave of the energy being absorbed. 

Sharp blades kill deer. You just have to get them to a spot that will cause enough bleeding for a quick kill. 

The lungs don't have much mass at all since they are full of air. 

You could kill a deer with just breaking the chest cavity and causing a pneumothorax with a needle. You won't have a blood trail but the deer will die. 

Fast and accurate = dead and smiling IMO


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## ThomasC4 (Nov 18, 2014)

Robert Carter said:


> View attachment 2094099


That is a very nice shot...! 

Congratulations...


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## ozarksbuckslaye (Jul 24, 2008)

Looks like he shanked its gizzard. That had to have stung a little bit. Congrats x2


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## rattus58 (Jul 9, 2007)

ozarksbuckslaye said:


> Yes sir that is correct all except the 6" part. Six feet wide is what I said. The gun is a Remington 700 BDL 7mm Ultra Mag with a 26" barrel. Nosler 140 grain ballistic tips on top of 94 grains of reloader 25 powder. She's a wicked beast.


This is a bang stick... :laugh:


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## weekender21 (Jan 27, 2012)

ThomasC4 said:


> I personally like the lightest arrows my bow can safely handle.
> 
> The speed of the arrow creates KE also.
> 
> ...


Thomas, you're likely to pass through any deer at any angle with that KE. However, the heavier arrow does give you more momentum and will technically penetrate better. Again, not likely to matter when you're shooting those numbers. Your bow will also be more quiet with the 530 grain arrow. 

Momentum with the 380 grain arrow=.556

Momentum with the 530 grain arrow=.658


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## Aronnax (Nov 7, 2013)

Many people like to dismiss physics and rely on personal experience of what works. But all the same physics applies to you regardless. And if knowing _what_ works is all that matters to you, then that's also fine dandy. But for me, understanding _why_ and _how_ things work is everything. In my career, it is my job to understand the how's and why's, and apply that knowledge to making a better product that my employers can manufacture, sell to consumers, and make a profit. I don't currently work in the archery business, but that doesn't stop my mind from being occupied by whatever thing it is that I find interesting at the moment. And right now, it's the whole process of how that deceptively simple looking bent stick takes energy from the muscles in my back, and puts it into an arrow, and how that arrow uses that energy to penetrate a target. 

Does that matter to the average 95% of bow hunters out there? Probably not. Just buy quality gear from reputable mfg's, be proficient with its use, and be happy.

BM


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## ThomasC4 (Nov 18, 2014)

weekender21 said:


> Thomas, you're likely to pass through any deer at any angle with that KE. However, the heavier arrow does give you more momentum and will technically penetrate better. Again, not likely to matter when you're shooting those numbers. Your bow will also be more quiet with the 530 grain arrow.
> 
> Momentum with the 380 grain arrow=.556
> 
> Momentum with the 530 grain arrow=.658


Okay now the other factor... Broadheads, I have seen some that are so blunted in the angle of the blade or the tip. All of this eats up energy and creates drag. 

I have not had a problem shooting though deer at any angle and I am shooting a 366 grain arrow at 280 fps. Which gives me 63 ft lbs of KE at the point of impact. Assuming the deer was 1 yard in front of me. 

I may go to one of the newer faster bows but I have a very long draw so it always makes finding one more difficult especially a used one. With these same arrows I will active the IBO speeds or with in 10 fps of it. I like to shoot at 60 lbs. I used to shoot at 73 lbs but I don't see the need anymore. 

I only shoot during hunting season and weeks before so my bow doesn't get a lot of wear.


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## Aronnax (Nov 7, 2013)

ThomasC4 said:


> I have not had a problem shooting though deer at any angle and I am shooting a 366 grain arrow at 280 fps. Which gives me 63 ft lbs of KE at the point of impact. Assuming the deer was 1 yard in front of me.


But a heavier arrow would stick deeper in the dirt after passing through the deer! 

Sorry, couldn't resist.

But here's a little graph, assuming there was a theoretical bow that had a constant efficiency and all arrows shot from it had a constant 30ke (reasonable trad bow number), how arrow mass changes velocity and momentum. In real life, KE also goes up with arrow weight but some small amount, so momentum in reality rises more than this graph shows, and velocity doesn't drop off quite as much.








BM


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## weekender21 (Jan 27, 2012)

ThomasC4 said:


> Okay now the other factor... Broadheads, I have seen some that are so blunted in the angle of the blade or the tip. All of this eats up energy and creates drag.
> 
> I have not had a problem shooting though deer at any angle and I am shooting a 366 grain arrow at 280 fps. Which gives me 63 ft lbs of KE at the point of impact. Assuming the deer was 1 yard in front of me.
> 
> ...


There are plenty of other factors. With modern equipment it's really only worth discussing because we're archery dorks. My wife killed her first animal with a bow in February. It was a smaller hog but I watched in amazement as her 360 grain arrow zipped through the hog, buried in the dirt, and snapped in half when he took off. The little boar fell in sight. She was shooting a Mathews Jewel, 35 LB DW @ 23.5" with the above mentioned 360 grain arrow. She was using a 4 blade slick trick standard that many (not me) claim isn't good for penetration due to the steep blade angle and number of blades, obviously there is more to it. 

Happy hunting.


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## ThomasC4 (Nov 18, 2014)

weekender21 said:


> There are plenty of other factors. With modern equipment it's really only worth discussing because we're archery dorks. My wife killed her first animal with a bow in February. It was a smaller hog but I watched in amazement as her 360 grain arrow zipped through the hog, buried in the dirt, and snapped in half when he took off. The little boar fell in sight. She was shooting a Mathews Jewel, 35 LB DW @ 23.5" with the above mentioned 360 grain arrow. She was using a 4 blade slick trick standard that many (not me) claim isn't good for penetration due to the steep blade angle and number of blades, obviously there is more to it.
> 
> Happy hunting.


Then the greatest factor is the deer itself. When they are on alert they contract the muscles either at the sound or as soon as hit, which then clamp down on the arrow shaft as it is moving though the deer. Sure you cut a hole in them but muscles can move a lot and with contractions, and the spin of the deer it all eats up energy.

Those standards only have a 1" cut on them, less resistance. But with the 4 blades I bet they do some damage.


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## ThomasC4 (Nov 18, 2014)

weekender21 said:


> With modern equipment it's really only worth discussing because we're archery dorks.


Hey them are fighting words...


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## DDSHOOTER (Aug 22, 2005)

Yep, shooting a 45# pound bow with a 450 grain arrow at 172 fps. Pretty well rounded setup.
Dan


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## benofthehood (May 18, 2011)

I have killed way too many animals with Cedar and alloy arrows that were between 8 and 10 gpp to even worry about it. Heck I never even used to weigh my arrows ... And heaps of them had the old Bodkin heads on them.
I then went to 10-12gpp and man did they hit hard , and the animals still died quickly and humanely ...
They didn't die any 'better' though.

IMHO big game , water buff etc are to be awarded their due respect so 'use enough gun' in terms of poundage and appropriate arrows.

But all of this is absolutely arbitrary if your arrows are not flying well and hitting the spot you are aiming at.

For deer, goats, pigs etc , arrow weight is neither here nor there for me , a good flying arrow that shoots where I am looking is all that matters.


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## Beendare (Jan 31, 2006)

ThomasC4 said:


> The speed of the arrow creates KE also.
> 
> A 380grain arrow flying at 330 fps has 91 ft lbs of KE
> A 530 grain arrow flying at 280 fps has 92 ft lbs of KE
> ...


Heres where I think most guys- especially compound guys lose it. They compare the two arrows- above- using "KE" as their criteria. Totally off base.

In my experience, the 530gr arrow above far out penetrates the 380gr- not even close when it comes to a big boar hog with thick shield. The KE comparison tells you nothing....


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## weekender21 (Jan 27, 2012)

Yep

Those who compare big boars to deer are greatly underestimating the boar.


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## ThomasC4 (Nov 18, 2014)

Beendare said:


> Heres where I think most guys- especially compound guys lose it. They compare the two arrows- above- using "KE" as their criteria. Totally off base.
> 
> In my experience, the 530gr arrow above far out penetrates the 380gr- not even close when it comes to a big boar hog with thick shield. The KE comparison tells you nothing....


How does it tell you nothing? 

Energy is the ability to do work. 

The work is cutting...

All this energy is focused in the diameter of the arrow and the blades of the broad head. 

If I put the arrow though the deer before it even knows it because, I have a quiet and fast bow all the better. I like light and fast because I only have 1 pin... Just put it on them and pull the trigger.


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## weekender21 (Jan 27, 2012)

After impact the heavier arrow carries more momentum and therefore more penetration potential. KE doesn't tell you nothing, just not the full story.


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## ThomasC4 (Nov 18, 2014)

weekender21 said:


> After impact the heavier arrow carries more momentum and therefore more penetration potential. KE doesn't tell you nothing, just not the full story.


Oh I know that, I just think momentum is being overrated. Since the arrow is cutting its way though the deer. It is not a wrecking ball where momentum is what does the work.


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## rattus58 (Jul 9, 2007)

ThomasC4 said:


> Oh I know that, I just think momentum is being overrated. Since the arrow is cutting its way though the deer. It is not a wrecking ball where momentum is what does the work.


I'm hoping you're making these comments facetiously. Momentum is what keeps the arrow cutting and to a degree, on track in the animal.


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## weekender21 (Jan 27, 2012)

Could be overrated until you need it. Doesn't really matter how deep your arrow penetrates into the dirt after passing through your buck. Eventually you'll hit heavy bone and the extra momentum pays off. I hunt hogs a lot and use the same set up for them as I do for deer, goats, sheep, turkey's, etc. To me, it's not overrated...if anything, momentum is underrated and generally not considered by archers.


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## ThomasC4 (Nov 18, 2014)

rattus58 said:


> I'm hoping you're making these comments facetiously. Momentum is what keeps the arrow cutting and to a degree, on track in the animal.


No I am not, since all arrows have momentum. Which can be increased more, energy or momentum? Maybe I am not understanding this quite right? Wouldn't be the first time. :wink:


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## Beendare (Jan 31, 2006)

*What?*



weekender21 said:


> Could be overrated until you need it. Doesn't really matter how deep your arrow penetrates into the dirt after passing through your buck. Eventually you'll hit heavy bone and the extra momentum pays off. I hunt hogs a lot and use the same set up for them as I do for deer, goats, sheep, turkey's, etc. To me, it's not overrated...if anything, momentum is underrated and generally not considered by archers.


 You do realize we are saying the same thing, right?
I've shot both arrows in your example [both about the same KE] into hogs like this that had a 1" thick shield.......which do you think was better by a wide margin?


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## JParanee (Oct 13, 2009)

Robert Carter said:


> View attachment 2094099


Great pic


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## Robert Carter (Apr 2, 2014)

Comparing arrows from a compound to those from a recurve is not anywhere near apples to apples . Crank your compound till is shoots those arrows at about 170 fps then you will see the benefit of the heavier arrow. RC


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## rattus58 (Jul 9, 2007)

ThomasC4 said:


> No I am not, since all arrows have momentum. Which can be increased more, energy or momentum? Maybe I am not understanding this quite right? Wouldn't be the first time. :wink:


 Kinetic energy is measured by taking speed and multiplying it by itself, squaring it. That is the basic component of Kinetic Energy (KE). As you can see, that any drag, slowing, impediment to speed, will also change KE, proportionately, or a rapid loss of work. Momentum isn't sexy. Momentum is the guy in the overalls and is mass (weight) times velocity. KE and Momentum in inextricably linked by velocity.

grains	400
speed	300
Bullet Diameter	0.359375
KE	79.92007992
Momentum	0.532800533
momentum_1	5.328005328
Taylor	6.160714286

grains	400
speed	270
Bullet Diameter	0.359375
KE	64.73526474
Momentum	0.47952048
momentum_1	4.795204795
Taylor	5.544642857

Why momentum is more germane, is that this same 10% loss of velocity equates to about an 11% loss of momentum, realistic. As to work... momentum is what carries the arrow or bullet once it leaves the string/muzzle. There is no more acceleration and there is only drag left. Momentum and Ballistic Coefficient determine the result and also when the projectile hits the target.

Aloha...


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## weekender21 (Jan 27, 2012)

Beendare said:


> You do realize we are saying the same thing, right?
> I've shot both arrows in your example [both about the same KE] into hogs like this that had a 1" thick shield.......which do you think was better by a wide margin?
> View attachment 2094493


Beendare, you do realize this isn't my thread and I'm agreeing with you 100% right? Heavy arrows = better penetration. Simple undebatable physics.

I didn't post an example but let me guess....the heavy arrow by a wide margin.


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## weekender21 (Jan 27, 2012)

Another thought on momentum indirectly related to this debate...

The lighter arrow with less momentum leaves the string faster but also bleeds speed faster than the heavier arrow with more momentum. Additionally, the lighter arrow with less momentum is more susceptible to wind. Same with guns, light fast bullet vs. Heavy slower (at the muzzle) bullet. 

These little details are not likely to matter unless you're at one extreme or the other....but, I like details.

Happy Thanksgiving to all, regardless of your choice of arrow!!!


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## ThomasC4 (Nov 18, 2014)

rattus58 said:


> Kinetic energy is measured by taking speed and multiplying it by itself, squaring it. That is the basic component of Kinetic Energy (KE). As you can see, that any drag, slowing, impediment to speed, will also change KE, proportionately, or a rapid loss of work. Momentum isn't sexy. Momentum is the guy in the overalls and is mass (weight) times velocity. KE and Momentum in inextricably linked by velocity.
> 
> grains	400
> speed	300
> ...



Okay, I think I understand what you are getting at now. :BangHead:

I will still be using a 366 grain arrow though I need the single pin. When I was younger and shooting at deer with my Bear Polar LTD I would always misjudge the distance and so I would miss. Not anymore distance is no longer an issue...


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## CAPTJJ (Dec 24, 2007)

Happy Thanksgiving everyone.


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## BarneySlayer (Feb 28, 2009)

I think we have a disconnect of what momentum means in a colloquial sense, versus what it means when you use numbers.

KE is rated in foot*pounds. 30 ftlbs of KE is enough to push 30 pounds of force over a distance of 1 foot, 15 pounds of force for 2 feet, 10 pounds for 3 feet, etc.

Seems relevant. How much force do you think is required to push a sharp knife 1 inch wide through flesh and bone? I haven't measured it, but considering how easily you can cut off the legs of a deer, I wouldn't venture that it is a whole lot.

Now, you can say that some bows will get more KE out of a heavier arrow (and as a result leave less in the bow, resulting in a quieter bow). You can also say that due to the behavior of fluids, IF the arrow is penetrating a medium that is or behaves like a fluid, which offers more resistance to faster moving objects, that faster arrow will lose more energy due to displacing mass required for cutting.

However, the idea that slowing down a light arrow faster decreases penetration shows a misunderstanding of Newtonian physics. Energy is by definition, the ability to do work. Work can be defined (Is defined), as force times distance. If you're talking about doing work, equal KE is equal KE, and momentum has nothing to do with it. A faster, lighter arrow may slow faster, but if the resistance is equal (which will depend on the medium), since it begins with more velocity, with equal KE, it takes the same distance (penetration) to stop. It is also conceivable that some substances may resist slower projectiles more effectively, because a slower object allows the object to be penetrated to more gradually accellerate, flex, or move, spreading the energy put into it over a longer time, and therefore over a greater area. IOW, a softer catch.

I am not advocating lighter arrows over heavy, but call it what it is- better energy transfer to the arrow (the degree of which will depend on the bow and arrow details), less drag through the air, and likely less resistance from the medium (which will depend somewhat on what part of the animal you're cutting through, but for the parts heavily fluid- laden, most likely.)

Momentum, from a physics standpoint, has NOTHING to do with it. Momentum is important when you're talking about one object moving another. Knock down, shock value. Remember the actual physics problems we did when we actually calculated momentum, and the calculation gave us a real result? I do.


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## weekender21 (Jan 27, 2012)

A property of a moving body that the body has by virtue of its mass and motion and that is equal to the product of the body's mass and velocity; broadly : *a property of a moving body that determines the length of time required to bring it to rest* when under the action of a constant force or moment

Momentum absolutely has something to do with _it_.

All the hunting shows you see with 6" of penetration are great illustrations. Blazing fast light arrows with great KE and not so great momentum.


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## Matt_Potter (Apr 13, 2010)

Good god - we are talking about deer. They keel over if you look at them funny. 

8-10 GPP - tune your bow - screw in a broad head and go hunt.


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## rattus58 (Jul 9, 2007)

BarneySlayer said:


> I think we have a disconnect of what momentum means in a colloquial sense, versus what it means when you use numbers.
> 
> KE is rated in foot*pounds. 30 ftlbs of KE is enough to push 30 pounds of force over a distance of 1 foot, 15 pounds of force for 2 feet, 10 pounds for 3 feet, etc.
> 
> ...


Hahahahahahaha...... I'm surprised anyone would actually say something like that in public......


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## rattus58 (Jul 9, 2007)

Matt_Potter said:


> Good god - we are talking about deer. They keel over if you look at them funny.
> 
> 8-10 GPP - tune your bow - screw in a broad head and go hunt.


Finally.... :grin:


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## kegan (Aug 28, 2006)

Matt_Potter said:


> Good god - we are talking about deer. They keel over if you look at them funny.
> 
> 8-10 GPP - tune your bow - screw in a broad head and go hunt.


A lot of these threads make me wonder how anything has been killed with a bow and arrow since it's clearly so difficult to get adequate penetration.


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## ozarksbuckslaye (Jul 24, 2008)

rattus58 said:


> This is a bang stick... :laugh:
> 
> View attachment 2094109


I was already well aware of that. Around these parts is typical to hear someone refer to a deer rifle as a boom stick or a bang stick.


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## Chris1ny (Oct 23, 2006)

Deer any arrow will do. Bear, definitely the heavier one.


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## reddogge (Jul 21, 2009)

Back in 1967 things were a lot simpler and somehow managed to kill deer.


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## Matt H (Aug 23, 2014)

does a honda civic going 60 mph go through a brick wall any better/worse than a bronco going 45 mph?

adding around 10 grams to an arrow makes a difference but a lighter arrow isn't going to bounce off a deer (penetration test around 5:20 of the video)
[video=youtube_share;w0hJ5HrXN1k?t=5m21s]http://youtu.be/w0hJ5HrXN1k?t=5m21s[/video]

i'm shooting arrows at 8.1 gpi total arrow weight around 390 grains. i'm more worried about making a good shot than i am about what difference 10 grams will do

edit: i think the biggest difference is the speed of the arrow, from the videos captjj posted, 210ish fps is about 145mph, 175ish fps is 120 mph, how much of a difference does that make in 10,20,30 yard distances?


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## ozarksbuckslaye (Jul 24, 2008)

weekender21 said:


> A property of a moving body that the body has by virtue of its mass and motion and that is equal to the product of the body's mass and velocity; broadly : *a property of a moving body that determines the length of time required to bring it to rest* when under the action of a constant force or moment
> 
> Momentum absolutely has something to do with _it_.
> 
> All the hunting shows you see with 6" of penetration are great illustrations. Blazing fast light arrows with great KE and not so great momentum.


Yeah I don't think so. If anything they're great illustrations of what to expect from large expanding broadheads. I know some are going to pitch a fit but I've shot arrows of extreme different weights into foam using the same 70 pound bow and the light arrows shot deeper. I'm talking like 1,300 grains vs. 350 grains. Call me crazy but real world results are way more important to me than back and forth discussions about math equations.


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## rattus58 (Jul 9, 2007)

kegan said:


> A lot of these threads make me wonder how anything has been killed with a bow and arrow since it's clearly so difficult to get adequate penetration.


especially with one of your Omega's... :laugh: which by the way, casts 700 grain arrows with surprising speed for such a light weight bow. Impressive....


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## Matt H (Aug 23, 2014)

some numbers from the book Timeless Bowhunting by Roy S. Marlow

View attachment 2094721


the numbers don't lie, but do the numbers matter if arrows of differing weights get the job done equally effectively?


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## FORESTGUMP (May 14, 2008)

benofthehood said:


> I have killed way too many animals with Cedar and alloy arrows that were between 8 and 10 gpp to even worry about it. Heck I never even used to weigh my arrows ... And heaps of them had the old Bodkin heads on them.
> I then went to 10-12gpp and man did they hit hard , and the animals still died quickly and humanely ...
> They didn't die any 'better' though.
> 
> ...



Exactly, and, I never needed a scientific calculator to tell me which arrow flies the best to where I'm looking and hits with good authority upon arrival. Quite simple really.


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## Cris Anderson (Oct 22, 2014)

ozarksbuckslaye said:


> Yeah I don't think so. If anything they're great illustrations of what to expect from large expanding broadheads. I know some are going to pitch a fit but I've shot arrows of extreme different weights into foam using the same 70 pound bow and the light arrows shot deeper. I'm talking like 1,300 grains vs. 350 grains. Call me crazy but real world results are way more important to me than back and forth discussions about math equations.


Foam is substantially different than a blood filled deer too. The physical properties of the target have a big impact on this kind of thing from a physics standpoint.

Again, I don't have a prerogative on this. The fact is...at 27" draw, I'm not shooting 500g arrows out of anything. But the difference between 350 and 450 are worth looking into for me.


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## BarneySlayer (Feb 28, 2009)

rattus58 said:


> Hahahahahahaha...... I'm surprised anyone would actually say something like that in public......
> View attachment 2094688


Glad to entertain you


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## Matt H (Aug 23, 2014)

at the end of the day it's a personal choice, no right or wrong on this one. for me having a flatter trajectory and less flight time to impact on target outweighs any potential benefits of penetration with a heavier arrow which can be achieved with good shot placement no matter what arrow is used.


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## BarneySlayer (Feb 28, 2009)

Rest easy, I've done some hardly scientific tests instead of definitive proof.


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## ozarksbuckslaye (Jul 24, 2008)

Cris Anderson said:


> Foam is substantially different than a blood filled deer too. The physical properties of the target have a big impact on this kind of thing from a physics standpoint.
> 
> Again, I don't have a prerogative on this. The fact is...at 27" draw, I'm not shooting 500g arrows out of anything. But the difference between 350 and 450 are worth looking into for me.


Yeah I understand what you're saying about the matter difference between targets. 

The point I was hoping to make was that I shot 2 different arrows into a target, one having twice as much momentum as the other and the one with the least amount penetrated the farthest. 

The proof is in the puddin'. If one arrow has twice the momentum of another, some people may get the idea the one with double the amount will penetrate twice as deep. Anyone who thinks that may be the case will be thoroughly disappointed with their results. I'm just here to tell people that is not how it works in the real world. 

The kinetic energy of an object can be described as the amount of force required to stop the object. It's as simple as that. End of story.


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## ThomasC4 (Nov 18, 2014)

BarneySlayer said:


> Rest easy, I've done some hardly scientific tests instead of definitive proof.


That was some nasty water coming out of those milk jugs...


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## BarneySlayer (Feb 28, 2009)

Rattus, let me elaborate. I can see how it may seem that what I'm saying is ridiculous.

Momentum, the dictionary definition, the English words, imply penetration. I'm not arguing that.

The momentum numbers you're putting forth are a unit of measurement used in physics, not to determine penetration, but to determine things like if object A, with a certain mass and velocity, collides with object B, with a certain mass and velocity, after the collision, what is going where, how fast, and in what direction.

IF you want to figure out what it will take, in terms of resistance over a distance, to stop a moving object, of any weight, the unit you calculate first is the Kinetic Energy of the moving object you want to stop. How hard (force) and how long (distance). It is as simple as that.

Let's do a thought experiment, and if you want to do it for real, get back to me about it.

Steel can of chili, pick your brand. I was going to use a squirrel in a coffee can, but I can only be so cruel 

Put that can of chili on a table, any table, or on top of a tree stump, whatever.

Shoot it with a 300 gn arrow moving at 300 fps. Compound bow would work. I'd bet $1 that it will pop right through it. Might even do it with a blunt, but I won't wager real money on a pass through, because I haven't tried it. Maybe I will 

Charter a freight train. Any kind you want, as many cars behind it as you want, as much momentum as you want. It can be dragging Mt. Shasta. Mount an arrow on the front, about half a can of chili high from the bottom of the wheels.

Put that can of chili on the track. Aim however you like. Use a sight, gap, track walk....

Now, get that train up to 1 fps before you hit that can of chili. You can even use more track than the power stroke of that compound bow. 

If you had welded that can of chili to the track, I'd say that you've got it made, but you didn't. 

Good luck with that momentum 

Yes, that's an extreme example, but my point is, it isn't the momentum that predicts penetration. You can counter that the train also has a lot of KE, and that didn't help it either. Valid point.

What I'm getting at is that the momentum units you're using have no direct application to an actual physics calculation. It may very well be that putting the same energy into a slower arrow could be, truly advantageous, for a lot of reasons. However, if you look at it from a physics problem standpoint, it's really complicated. If the medium to be penetrated was purely resistive, KE calculations would tell you everything, but in the scenario for hunting, the details get in the way. The higher velocity of the faster arrow introduces more air resistance (air is a fluid, in that sense). The nature of the fluid in the blood of an animal can offer more resistance to a faster moving object as well. When you see some of those effects, I can see why looking at momentum as a predictor seems tempting, and it might _seem_ more predictive, and may be in your experience, but it will invariably depend on what you're shooting, and what you're shooting it with.

To be clear, I'm speaking of this only in an academic context. If it works, it works, and I'm more inclined to draw from the experiences of people who've done it, both successfully and not.

Aloha to you


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## weekender21 (Jan 27, 2012)

ozarksbuckslaye said:


> Yeah I don't think so. If anything they're great illustrations of what to expect from large expanding broadheads. I know some are going to pitch a fit but I've shot arrows of extreme different weights into foam using the same 70 pound bow and the light arrows shot deeper. I'm talking like 1,300 grains vs. 350 grains. Call me crazy but real world results are way more important to me than back and forth discussions about math equations.


I completely agree, the large expanding broadheads are certainly part of the poor penetration equation, just didn't want to go down that road. I do think those archers shooting large mechanicals would be much better off with heavier arrows.

I'll have to also agree that there is a point of diminishing returns and I think you eluded to that with your 1,300 grain vs. 350 grain test. 

And lastly I concur that there is no replacement for real world experience on animals and for me, heavier arrows (445 grains +) have penetrated better than arrows in the 400 grain range. But I did watch my wife's 360 grain arrow zip through a hog!


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## ozarksbuckslaye (Jul 24, 2008)

weekender21 said:


> I completely agree, the large expanding broadheads are certainly part of the poor penetration equation, just didn't want to go down that road. I do think those archers shooting large mechanicals would be much better off with heavier arrows.
> 
> I'll have to also agree that there is a point of diminishing returns and I think you eluded to that with your 1,300 grain vs. 350 grain test.
> 
> And lastly I concur that there is no replacement for real world experience on animals and for me, heavier arrows (445 grains +) have penetrated better than arrows in the 400 grain range. But I did watch my wife's 360 grain arrow zip through a hog!


Yup you're right. Math has never been my strong point but I'm pretty sure it agrees with everything you just said. Heavier arrows should in most cases have the upper hand slightly when it comes to penetration in a fair test.


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## rattus58 (Jul 9, 2007)

BarneySlayer said:


> Rattus, let me elaborate. I can see how it may seem that what I'm saying is ridiculous.
> 
> Momentum, the dictionary definition, the English words, imply penetration. I'm not arguing that.
> 
> ...


All that is well and good..... Speed... and three hundred feet per second should do a decent job of penetration, especially with skinny arrows in any typical game found in America. However, KE as measured at the muzzle or as the bow leaves the string... ahem... the arrow... is now a by product of momentum. Sorry, but that is just the way it is. It is the arrows own weight and balance that matters once the arrow is in free flight. It is that momentum that takes the arrow through whatever medium you are shooting into. Two arrows of equal diameter and similar drag coefficient, whether at the muzzle, the string, or in flight, the arrow/bullet with the most momentum is going to win unless something odd befalls it.

My own arrows rarely get anywhere near 200 fps except in my Quillan Bow and a gargantuan Deathwish by Welte that I shot my first deer with, primarily because of their weight, averaging over 700 grains, and their size, 3/8" tapered in varying degrees to 11/32 or 5/16 and occasionally some funny business at the forend where I've tapered to a diameter less than what was necessary for good fit of a broadhead... and don't ask what i was thinking.. but they work ok... sooo... till I break them and I'm finding hickory to be difficult in that respect.. :grin:... however on to the reality of my life and penetration... My arrows always penetrate right through the animal... or at least the broadhead does. But they also have a lot of drag, both in flight and in media. They are fat and they are draggy with large snuffer broadheads leading the way and I can with some confidence say it is not kinetic energy driving the arrows through my game regardless of direction.. it is the sheer weight of the arrow doing the work which also I might add, keeps the arrows on course.... breaking bone when it meets it. Light arrows don't often survive a terminus of bone... heavy arrows rarely have difficulty with them.. this is momentum, not kinetic energy driving... kinetic is along for the ride at this point.

Much Aloha...


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## MGF (Oct 27, 2012)

Momentum MV and KE (MV^2)/2 are kind of tied together. When talking about a given bow, adding weight means losing velocity and changing trajectory. There may be a point for a given bow where energy is maximized (because of efficiency) but you can't have everything so I think it depends on what you're hunting and under what conditions.

For deer, I suspect that anything will work as long as it isn't so light that it breaks the bow.


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## BarneySlayer (Feb 28, 2009)

rattus58 said:


> All that is well and good..... Speed... and three hundred feet per second should do a decent job of penetration, especially with skinny arrows in any typical game found in America. However, KE as measured at the muzzle or as the bow leaves the string... ahem... the arrow... is now a by product of momentum. Sorry, but that is just the way it is. It is the arrows own weight and balance that matters once the arrow is in free flight. It is that momentum that takes the arrow through whatever medium you are shooting into. Two arrows of equal diameter and similar drag coefficient, whether at the muzzle, the string, or in flight, the arrow/bullet with the most momentum is going to win unless something odd befalls it.
> 
> My own arrows rarely get anywhere near 200 fps except in my Quillan Bow and a gargantuan Deathwish by Welte that I shot my first deer with, primarily because of their weight, averaging over 700 grains, and their size, 3/8" tapered in varying degrees to 11/32 or 5/16 and occasionally some funny business at the forend where I've tapered to a diameter less than what was necessary for good fit of a broadhead... and don't ask what i was thinking.. but they work ok... sooo... till I break them and I'm finding hickory to be difficult in that respect.. :grin:... however on to the reality of my life and penetration... My arrows always penetrate right through the animal... or at least the broadhead does. But they also have a lot of drag, both in flight and in media. They are fat and they are draggy with large snuffer broadheads leading the way and I can with some confidence say it is not kinetic energy driving the arrows through my game regardless of direction.. it is the sheer weight of the arrow doing the work which also I might add, keeps the arrows on course.... breaking bone when it meets it. Light arrows don't often survive a terminus of bone... heavy arrows rarely have difficulty with them.. this is momentum, not kinetic energy driving... kinetic is along for the ride at this point.
> 
> Much Aloha...


I understand what you're saying, and in what I believe you mean by it, I think you're right. Furthermore, I think I was wrong to say it the way that I did, when I said the momentum has nothing to do with it, as momentum is something that will accompany KE, inherently. I should have said that it is coincidental. Similarly, when you say, "this is momentum, not kinetic energy driving... kinetic is along for the ride at this point." I would say that you can give credit to one or the other as the driver, but there is only momentum because there is KE. It could very be more effective because it was invested in mass, which I think is more or less what you're saying. So, like I said, in what I believe you mean by it, I think you're right. I am, to a large part, getting hung up on labels that most everybody else will have no use for.


You've got a lot of experience putting arrows through animals, far more than I, and I value that experience, and put it in my mental log books. If I ever make it to whatever island you're on, and you've got time, I'd be happy to buy you dinner and a couple beers to hear some stories.

Falling back into the academic speculative side, that thought experiment with the chili can pointed out something to me that I had ignored. Apart from KE and momentum, _speed_ is an absolutely necessary component. To apply force to an object (i.e., cut), that object needs to provide resistance through inertia. That object, be it the whole animal, the local mass at the head (a rib, a shoulder blade, the flesh between ribs, etc), if not absorbing energy by the cutting, will absorb energy via acceleration. f=ma, and by extension a=f/m. If the object is lighter (less m), it will accelerate more. The more it can move (get pushed back), the more distance (and time) it has to absorb energy. The side effect is that the instantaneous peak force applied (and subsequently the pressure applied at the front of the broadhead), which is the most relative when trying to push through hard substances that require breaking, will be higher the faster the projectile is moving, and the _heavier_ the particular object being penetrated.

In other words, a slower moving projectile will allow the mass in front of it to flex more before breaking. If it was a borderline case of getting through something hard, it could be that with equal KE, the slower moving object would allow something to flex, dent and stop rather than break/cut.

not so great example, you can lop off the top of a blade of grass with a fast moving switch, with very little KE or momentum, and yet try doing that by swinging a 9 pound splitting maul.

Still, the point arises, that if you have enough speed, and can generate enough peak force on whatever impediments are in the way, or you shoot Matt Potter's favorite elk in the shoulder, it really doesn't matter. 

But, it's fun to think about.


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## Cris Anderson (Oct 22, 2014)

I watched a video where a guy got a pass through (well, the broadhead came out the other side about 12" if I recall) on a deer with a 35lb stick bow, a sharks tooth broadhead, and a cane arrow. I seriously think we're overthinking this some when it comes to deer. When he hit shoulder however, that arrow stopped dead, which is where my attention to this topic is being drawn in. I'm using OnTarget2 to design my arrows. It gives me numbers for arrow weight, velocity (INCREDIBLY ACCURATE to my chronograph experiences!), FOC%, KE, momentum, and even trajectory. I can see the measured differences in momentum and KE with just a mouse click...both off the string, and at the target. My problem is I don't know what those numbers translate to in the real world.

For example:









Here I have a light arrow build. The arrows are Arrow Dynamics Nitro Stinger XLT. The bow is a 2015 Xpedition Xcentric. Arrow weight is 355g, velocity is 314fps at the bow.









And here is the heavy build. The arrows are Black Eagle X-Impacts, out of the same bow. Arrow weight is 436g, with 285fps velocity at the bow.

Now, for the interesting part:









Light arrow.









Heavy arrow.

Taking FOC out of the equation, it's pretty obvious which arrow will penetrate farther. What I thought was interesting was that the heavy arrow only lost 6fps over 40yds, while the light arrow lost 10fps. This makes sense of course, as an object travelling faster will have more resistance to its speed...and if that object is lighter, it will have less momentum to push it through that resistance.

Again, I don't know what these KE and momentum numbers mean when compared with game animals other than deer, or when compared to a dead on shoulder hit vs a clean hit to the vitals. I just figured some of you might find them interesting.


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## BarneySlayer (Feb 28, 2009)

Cris Anderson said:


> What I thought was interesting was that the heavy arrow only lost 6fps over 40yds, while the light arrow lost 10fps. This makes sense of course, as an object travelling faster will have more resistance to its speed...and if that object is lighter, it will have less momentum to push it through that resistance.


It makes sense that a light arrow would lose more speed, energy, and momentum over distance. Air resistance is exponential with speed. If you're on a motorcycle, you get a really good example of this, particularly if you don't have a front fairing. 25 mph it's like a nice breeze. 50 mph feels kind of serious. 75 mph, you'd really prefer to keep your head down and in front of you. 100 mph, if you're not tucked in behind something, the wind will put your helmet into your face.

What's also significant about that difference, is that at higher speeds, a given loss in fps reflects more energy at high speeds than low, since it takes exponentially more energy to get an object to speed up more once it already has speed. Reason? Since you begin faster, and end faster, you have to push it over more distance. Want an object to go twice as fast? It'll take 4 times the energy, _at least_. When you throw in the fact that during the latter part, you're accelerating it through greater wind drag because of the higher speed, it'll take even more.


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## rattus58 (Jul 9, 2007)

BarneySlayer said:


> I understand what you're saying, and in what I believe you mean by it, I think you're right. Furthermore, I think I was wrong to say it the way that I did, when I said the momentum has nothing to do with it, as momentum is something that will accompany KE, inherently. I should have said that it is coincidental. Similarly, when you say, "this is momentum, not kinetic energy driving... kinetic is along for the ride at this point." I would say that you can give credit to one or the other as the driver, but there is only momentum because there is KE. It could very be more effective because it was invested in mass, which I think is more or less what you're saying. So, like I said, in what I believe you mean by it, I think you're right. I am, to a large part, getting hung up on labels that most everybody else will have no use for.
> 
> 
> You've got a lot of experience putting arrows through animals, far more than I, and I value that experience, and put it in my mental log books. If I ever make it to whatever island you're on, and you've got time, I'd be happy to buy you dinner and a couple beers to hear some stories.
> ...


What makes all of this irrelevant is a tornado. I've seen pictures of straw driven through telephone poles... :laugh: And if you're ever over this way, be happy to join you for libation... or dinner... especially if we still have any hunting going on here... :grin:


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## rattus58 (Jul 9, 2007)

BarneySlayer said:


> It makes sense that a light arrow would lose more speed, energy, and momentum over distance. Air resistance is exponential with speed. If you're on a motorcycle, you get a really good example of this, particularly if you don't have a front fairing. 25 mph it's like a nice breeze. 50 mph feels kind of serious. 75 mph, you'd really prefer to keep your head down and in front of you. 100 mph, if you're not tucked in behind something, the wind will put your helmet into your face.
> 
> What's also significant about that difference, is that at higher speeds, a given loss in fps reflects more energy at high speeds than low, since it takes exponentially more energy to get an object to speed up more once it already has speed. Reason? Since you begin faster, and end faster, you have to push it over more distance. Want an object to go twice as fast? It'll take 4 times the energy, _at least_. When you throw in the fact that during the latter part, you're accelerating it through greater wind drag because of the higher speed, it'll take even more.


Wind resistance is an interesting phenomena... it takes four times the thrust to double the speed in free air. :laugh:


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## Matt H (Aug 23, 2014)

something i noticed about all the penetration tests, as far as i can tell, they're all using field points. not a good test on what a broadhead does to that transfer of energy into cutting force. and different broadheads use that energy differently. mechanicals eat up a lot of energy just opening the cutting blades. dull blades eat up a lot of energy by losing more energy into the meat than a sharp blade.

from your numbers Cris

the difference between the 355 grn arrow and 436 grn arrow is about 5 grams. 314 fps is 214mph, 285fps is 194mph. how much of a difference does 5 grams do at those speeds? will 20mph difference diminish/benefit bone breaking power +/- 5 grams of weight at those speeds? maybe it will make a difference at lower draw weights but theres a limit at which speed nulls the argument of arrow weight and becomes an argument of materials. sharp thick bladed broadhead compared to a sharp thin bladed broadhead. carbon vs aluminum vs wood shaft. coc vs mechanical. even vanes vs feathers causing drag once it hits a deer body.

the numbers can give you a good idea what a bow and arrow are capable of but doesn't paint the whole picture of how all the components work together. most of us use the benefit of extra energy by using as high a draw weight we can be accurate with. that 35lb selfbow wouldn't have penetrated a deer shoulder if he'd been using a heavier arrow.

it seems to me the argument is that a heavier arrow will travel further after contacting something solid than a light arrow, IF it breaks through the solid barrier. 

huge game withstanding.


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## rattus58 (Jul 9, 2007)

Matt H said:


> something i noticed about all the penetration tests, as far as i can tell, they're all using field points. not a good test on what a broadhead does to that transfer of energy into cutting force. and different broadheads use that energy differently. mechanicals eat up a lot of energy just opening the cutting blades. dull blades eat up a lot of energy by losing more energy into the meat than a sharp blade.
> 
> from your numbers Cris
> 
> ...


I was right with you till your 35 pound selfbow statement.... :grin:


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## BarneySlayer (Feb 28, 2009)

Matt H said:


> something i noticed about all the penetration tests, as far as i can tell, they're all using field points.


You obviously missed my awesome, future award winning documentary on the subject. I used broadheads 

Both the heavy and the light arrows, going pretty much the same speed, poked holes through a plastic gallon milk jug filled with water (our fluid medium), with enough speed left over, after passing all the way through, to sink into the foam broadhead target about 2/3 the length of the shaft. (The second light arrow shot actually went way deeper, since it hit the soft center of the foam block.), I could erroneously claim, with much controversy, that it definitively proves that both KE and momentum are an impediment to penetration, based on that data, but my ridiculousness does have limits 

Of course, my tests had all sorts of problems with data collection and application to real world scenarios, which I will abstain from listing them, as I have exceeded my thread quota. As much as I like talking about detailed hypothetical minutia for the recreational benefits, I realize that most people don't.

Okay, one thing... I think my hangup is based on what most people are referring to as momentum is, technically speaking, more related to inertia. More mass, more inertia, more resistance to slowing, on top of the benefits of lower velocity, being lower drag, lower fluid resistance, etc.... 

Somebody help me, I can't stop


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## rattus58 (Jul 9, 2007)

BarneySlayer said:


> You obviously missed my awesome, future award winning documentary on the subject. I used broadheads
> 
> Both the heavy and the light arrows, going pretty much the same speed, poked holes through a plastic gallon milk jug filled with water (our fluid medium), with enough speed left over, after passing all the way through, to sink into the foam broadhead target about 2/3 the length of the shaft. (The second light arrow shot actually went way deeper, since it hit the soft center of the foam block.), I could erroneously claim, with much controversy, that it definitively proves that both KE and momentum are an impediment to penetration, based on that data, but my ridiculousness does have limits
> 
> ...


Inertia, in my limited capacity as an educator, is resistance to movement... that is why your arrow bends around the riser on traditional risers... momentum is movement. You have momentum once in motion. Inertia might be considered in motion by resisting a change in direction by my way of thinking, but it would be incorrect to say that they are the same. Inertia in your example would be resistance to movement, not the other way around... as momentum has overcome inertia. :grin:

Aloha... :beer:


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## portablevcb (May 10, 2014)

FWIW, inertia is basically the mass of an object. The mass represents the resistance to change of momentum, ie, it takes more force to accelerate a larger mass than it does a smaller mass. Same with deceleration. Momentum is the state of an object described by it's mass and velocity. The mass and velocity also define it's kinetic energy. So, yes, all three are related by the mass.

This arguement sounds just like the ones over which pistols/rifles are better, which bullets are better and who can kill what faster.

Use what you have and learn to hit the vitals with it.


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## BarneySlayer (Feb 28, 2009)

rattus58 said:


> Inertia, in my limited capacity as an educator, is resistance to movement... that is why your arrow bends around the riser on traditional risers... momentum is movement. You have momentum once in motion. Inertia might be considered in motion by resisting a change in direction by my way of thinking, but it would be incorrect to say that they are the same. Inertia in your example would be resistance to movement, not the other way around... as momentum has overcome inertia. :grin:
> 
> Aloha... :beer:


The root of the word Inertia does indeed involve the property that a body at rest will stay at rest, (i.e., it is inert, unmoving) but the rest of what Inertia is, from a physics definition, is that a body in motion will tend to stay in motion. 

Don't take my word for it... Check out Newton's first law of motion.

http://en.wikipedia.org/wiki/Newton's_laws_of_motion

If you have a body at rest, you have to do work (put in energy), to put the body into motion (Accelerate it). In that sense, the lack of motion is overcome, and you have built up momentum, but the momentum did not overcome inertia, the energy put into accelerating the mass did. More accurately, nothing was overcome, it simply changed. If you want to pick nits, depending on the frame of reference, it can be moving faster, or slower. For instance, if you're near the equator and shoot west, you are, from a larger frame of reference, slowing the arrow so that the deer/pig/cow collides with a slower-moving object while riding on a moving surface . I like that idea, kind of hilarious actually. I killed the deer by slowing down my arrow, and decreasing speed, KE, and momentum altogether. HA!

I guess what I'm getting at, taking the very long way around to clarifying, is that inertia, a property of mass is, by definition, the resistance to deceleration of a moving object (which is, if you really want to get into minutia, the same as accelerating an object, if you have no absolute frame of reference.) Given the same amount of available KE, a heavier arrow will have more inertia, because it has more mass. The momentum is incidental, and gets to go along for the ride, again, if we're picking nits.

Man, I love the idea of a deer, riding a gigantic merry go round, flying into my arrow. I can't get that out of my head. now I'm wondering, at my latitude, just how fast I'd have to shoot an arrow straight west to stop it from moving (referenced to the center of the earth). On the equator, would be about 1000 m.p.h, which is definitely way out of archery range. Don't think California it's far enough north to diminish that to archery speeds....

I think I need to look up some spherical geometry equations, to figure out how far north (or south), I'd need to go to stop an arrow leaving the bow at 198 fps (relative to me)

Hold the phone, I'm an idiot. Trigonometry will do it, if you just think from inside of the sphere. BRB!


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## Matt_Potter (Apr 13, 2010)

Matt_Potter said:


> Good god - we are talking about deer. They keel over if you look at them funny.
> 
> 8-10 GPP - tune your bow - screw in a broad head and go hunt.


^^^^^^^^^^^^^


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## BarneySlayer (Feb 28, 2009)

Okay, did some number crunching, and if I did it right, I'm going to need to beat 82.37 degrees latitude. 









Not much up there on the North side. Maybe a little sliver of Greenland, or that thing next to it. I don't know if there are any deer that far north. Pretty sure there are no deer in Antarctica. Either way, it's too far for me to travel, and I don't want to hunt with a jacket on if I can help it. Might be easier to get passage on a bullet train with renegade wild hobo deer stowaways, and ask the conductor to slow down to 135 mph, just for awhile, so I can clear the train of unwanted hobo deer, from front to back. Maybe if we all throw in, we can make this affordable. Any takers?


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## BarneySlayer (Feb 28, 2009)

Matt_Potter said:


> ^^^^^^^^^^^^^


Okay, Matt, fine, have it your way 

I need to gloat in my apple coring accomplishments anyway, and fry some pumpkin in coconut oil.

Happy Thanksgiving!


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## Matt H (Aug 23, 2014)

BarneySlayer said:


> You obviously missed my awesome, future award winning documentary on the subject. I used broadheads


sorry, i was distracted by the chainsaw acapella choir 

i like watching primitive pathways penetration tests, really shows how different broadhead materials penetrate
52 lb osage selfbow with 500 grain rivercane arrow


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## ozarksbuckslaye (Jul 24, 2008)

ozarksbuckslaye said:


> I shot 2 different arrows into a target, one having twice as much momentum as the other and the one with the least amount penetrated the farthest.
> 
> The proof is in the puddin'. If one arrow has twice the momentum of another, some people may get the idea the one with double the amount will penetrate twice as deep. I'm just here to tell people that is not how it works in the real world.
> 
> The kinetic energy of an object can be described as the amount of force required to stop the object. It's as simple as that. End of story.


That little test proved doubling the amount of momentum did absolutely nothing for penetration. Okay now if you take those same two arrows and double their speed then you will witness a dramatic increase in penetration. Why? Because it's all about speed. Hot, nasty, bad-ass speed.
Mass without motion has no energy. Energy is a product of mass + motion.


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## Matt H (Aug 23, 2014)

ozarksbuckslaye;10716855 65 said:


> That little test proved doubling the amount of momentum did absolutely nothing for penetration. Okay now if you take those same two arrows and double their speed then you will witness a dramatic increase in penetration. Why? Because it's all about speed. Hot, nasty, bad-ass speed.
> Mass without motion has no energy. Energy is a product of mass + motion.


exactly. 500 gr arrow to 1000 gr arrow going from 1 1/4 oz to 2 1/2 oz isn't that big of a jump in weight and if the change in speed is marginal there's not going to be that much difference in penetration, if the weight change is even less like 5 - 10 grams (75 - 150 grains) there'll be even less difference. it works the same with bullets


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## Cris Anderson (Oct 22, 2014)

Interesting video, lol.


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## [email protected] (Feb 23, 2004)

In order to argue that a faster arrow will out penetrate a heavier arrow, you would have to change something in what provides the energy source..ie the bow. You would have to increase DW or DL to generate a higher velocity without changing the bow launching the heavier arrow.

A bow is a closed system. It creates and stores X amount of energy. How efficiently it applies the energy it stores depends on the weight of the projectile it launches. A lighter arrow absorbs less energy that a heavier arrow shot from the same bow. There are no bows that are more efficient with light arrows vs heavy arrows..none.

If you launch a light arrow 300gr and a heavy arrow 600gr from the SAME bow, the heavy arrow will have a lower velocity at launch but have higher KE and MO than the lighter arrow. The extra weight allows for more energy transfer. The bow is more efficient at transferring its stored energy because of the additional arrow weight. The heavier arrow will also retain more KE and MO downrange.

There is now way around the simple physics involved.

I help out with a 6th grade science experiment. What will penetrate better..a lighter faster arrow or a slower heavier arrow?

4 arrows were used. Shot from the same bow. Bow was re-tuned for each arrow to give a bullet hole thru paper (i.e. traveling perfectly straight) at the target impact distance. Target medium was layered 36"x36"x2". Each arrow was was shot ten times into virgin foam. Results recorded for penetration depth and averaged.

1) 1912 X7 w/65gr nibb, 295gr, 64.96
2) 1916 X7 W/125gr nibb, 437gr, 68.53KE 
Nearly identical in OD but 295gr VS 437gr..respectively

3) 2512 W/90gr nibb, 434gr TAW 68.54KE
4) 2512 W/200gr nibb, 544gr TAW 70.09KE
Identical OD, different weight

Guess the order of arrow penetration…best to worst.


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## rattus58 (Jul 9, 2007)

[email protected] said:


> In order to argue that a faster arrow will out penetrate a heavier arrow, you would have to change something in what provides the energy source..ie the bow. You would have to increase DW or DL to generate a higher velocity without changing the bow launching the heavier arrow.
> 
> A bow is a closed system. It creates and stores X amount of energy. How efficiently it applies the energy it stores depends on the weight of the projectile it launches. A lighter arrow absorbs less energy that a heavier arrow shot from the same bow. There are no bows that are more efficient with light arrows vs heavy arrows..none.
> 
> ...


If I had to guess, it would be 1912 @ 295 grain less penetration over the 437 grain regardless of the faster speed. With the the 2512 544 out penetrates the 434. Best would be 1916 @437 and that is only because my 3/8 have a lot of drag and I'm assuming the 2512 do as well.


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## Stone Bridge (May 20, 2013)

I did this test just as OSB did on Youtube. My findings were the same as OSB. Given the same arrow diameter, the lighter arrow penetrated slightly more than the heavier arrow when shot from the same bow, same draw length. Maybe the numbers say this should not happen, but for me, and for OSB on film, and for Jack Howard in the 1960s, the lighter, faster arrow drove in deeper. Not much deeper, but a measurable amount. 

Any arrow doing at least 130fps, of about any weight, with a decent broadhead will easily kill the biggest whitetail. They carry no armor. Deer die very easily if you puncture a lung or two. That doesn't take much at all. Every broadside shot I ever took on a whitetail with 310 grain arrows at only 200 fps slipped all the way through and into the dirt beyond. Some cut ribs in half enroute. Heavy arrows work very well. Light arrows work just as well and have the advantage of making longer shots easier. The reason I use them is the flat trajectory. If you like 600 grain arrow for deer you'll easily kill your animal. It really doesn't make any real difference. Lighter just makes shooting easier to make good hits with.


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## Matt H (Aug 23, 2014)

what if we framed the situation with different numbers since "light" arrows are just as lethal as "heavy" arrows.

using Cris Anderson calculations again

355 grn (0.8 oz) arrow/314 fps and 436 grn (1 oz) arrow/285 fps, weight difference is about 5 grams

for every 1/8 to 1/4 oz (roughly, i guess 5 g would be more like 3/16 oz) of weight added you're losing about 20 to 25 mph of velocity on release. his light arrow lost 10 fps (6mph) at 40 yds and his heavy arrow lost 6 fps (4mph) at 40 yards

314 fps is 214mph, 285fps is 194mph @ 40 yds 304 fps/208 mph, 279fps/190 mph

more numbers 

lets use 20 yards, arrow flight @ 314 would be app 0.19 seconds. at 285 fps the arrow has traveled roughly 54 ft in 0.19 seconds. halve the 40 yard losses above. 5 fps/3 mph for light arrow, 3 fps/2 mph for heavy arrow, it's still about 54 ft of travel for the heavy arrow compared to the 60 feet for the light arrow. it's a split second but on a moving target like an alert/twitchy deer what kind of difference could that make?

those numbers mean more to me than the ke/mo calculations. 

trajectory and arrow arc is a whole other equation i don't know how to do. but at 10/20/30/40 yards with a decently fast bow how far/fast does any arrow drop? would the different arrows be noticeable? 

would anyone be able to tell the differences without the numbers? could you be given an arrow blind, shoot it and be able to tell if it was a 350 grn arrow or a 500 grn arrow? i couldn't, maybe someone could tell the heavier arrow is flying a bit slower, maybe...


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## Windrover (Jan 6, 2012)

This penetration discussion inevitably makes huge unwarranted assumptions. Field points are not broadheads, foam is not animal. Foam is used for targets because it stops arrows. It stops them by gripping the shaft while penetrating and withdrawal. Every medium will have different resistance to penetration from different projectiles. Just as dirt in the above video shows different penetration so will animals be very different from foam. The 30.06 has 30 times the energy of an IBO bow yet it could not penetrate the dirt box. Yes it takes energy to penetrate but that is far far from the only factor. Advertisers have brainwashed the consumer about the huge energy of the modern bow. In reality bows of all types have tiny energy. Those of you who use blades know that a dull tool takes a lot of force to use. A really sharp blade requires almost no force at all to cut.
For once and for all , foam isn't animal.


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## Windrover (Jan 6, 2012)

Cris Anderson said:


> I watched a video where a guy got a pass through (well, the broadhead came out the other side about 12" if I recall) on a deer with a 35lb stick bow, a sharks tooth broadhead, and a cane arrow. I seriously think we're overthinking this some when it comes to deer. When he hit shoulder however, that arrow stopped dead, which is where my attention to this topic is being drawn in. I'm using OnTarget2 to design my arrows. It gives me numbers for arrow weight, velocity (INCREDIBLY ACCURATE to my chronograph experiences!), FOC%, KE, momentum, and even trajectory. I can see the measured differences in momentum and KE with just a mouse click...both off the string, and at the target. My problem is I don't know what those numbers translate to in the real world.
> 
> For example:
> 
> ...


Excellent observation there Cris. I too am a On-Target devotee. Nothing like having the facts. Nowhere in this thread so far have I seen any mention of Dr Ashby. Interesting that. Ashby is so far as I know the only person to have done extensive penetration testing on animals, albeit large animals. I suspect that if research tells us what we don't want to know we tend to ignore it. So what Dr Ashby found is that of the many factors affecting penetration, energy is not the most important by far. Read at http://www.alaskabowhunting.com/Dr.-Ed-Ashby-W26.aspx
This whole thread is kinda silly when you realize that energy is not the important factor in penetration.


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## Bobman (Dec 18, 2004)

I like heavy arrows because they really quiet the bow down and I only shoot at deer 20 yards and closer so trajectory isn't really an issue


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## weekender21 (Jan 27, 2012)

Doesn't matter past 20 with a range finder.


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## [email protected] (Feb 23, 2004)

rattus58 said:


> If I had to guess, it would be 1912 @ 295 grain less penetration over the 437 grain regardless of the faster speed. With the the 2512 544 out penetrates the 434. Best would be 1916 @437 and that is only because my 3/8 have a lot of drag and I'm assuming the 2512 do as well.


Yep. Heavy trumps light. Small OD trumps large OD given the same weight. 




Windrover said:


> This penetration discussion inevitably makes huge unwarranted assumptions. Field points are not broadheads, foam is not animal. Foam is used for targets because it stops arrows. It stops them by gripping the shaft while penetrating and withdrawal. Every medium will have different resistance to penetration from different projectiles.


Yes it will, but the penetration by the projectile will always be relative. An arrow that penetrates deeper in foam relative to another arrow will penetrate to the same relative depth in a different medium compared to the other arrow. The target medium does not matter in the sense that any given medium presents the same resistance to the projectile drag force. The projectile physics determines the penetration.




Windrover said:


> Just as dirt in the above video shows different penetration so will animals be very different from foam. The 30.06 has 30 times the energy of an IBO bow yet it could not penetrate the dirt box. Yes it takes energy to penetrate but that is far far from the only factor.


Again..it's not the target medium it's the projectile..because of the physics involved. Velocity creates huge drag/resistance for the 180gr 30'06 at 2800fps because of the velocity. If you double velocity, drag force goes up by a factor of 4. In simplistic terms and arrow traveling at 280fps vs a bullet at 2800fps the drag force difference is huge. Drag force is what slows the projectile. 




Windrover said:


> Yes it takes energy to penetrate but that is far far from the only factor. Advertisers have brainwashed the consumer about the huge energy of the modern bow. In reality bows of all types have tiny energy. Those of you who use blades know that a dull tool takes a lot of force to use. A really sharp blade requires almost no force at all to cut. For once and for all , foam isn't animal.


Agreed. Not the only factor. But..if all factors regarding an arrow are kept the same except for weight, the heavier arrow will win the penetration contest.


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## Matt H (Aug 23, 2014)

it's all an interesting physics lesson and no one is changing physics. heavier objects carry more force than lighter objects despite velocity. a heavier arrow will penetrate further than a light arrow, but light arrows can double lung a deer same as a heavy arrow, does it matter after that?

it comes back to personal preferences: Bobman likes heavier arrows because they help quiet his bow, I'm ok with lighter arrows because my recurve is quiet and i like faster arrows. no matter what weight arrows you use make sure your broad heads are sharp and don't shoot a deer in the butt.


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## Cris Anderson (Oct 22, 2014)

So, here's a question. The heavy arrow I posted above has a momentum at 40yds of .5400ish. The lighter arrow is at .4800. What do you guys who prefer heavy arrows recommend for various game animals? There's plenty of KE charts...but nothing for momentum. I know full well that Dr. Ashby prefers an arrow weight of over 600 grains period, which will translate into 240fps or so out of my bow at my draw length, and .6400 momentum at 40yds. I'd like to keep my arrow speed up around 270-280fps preferably. Working backward that puts my arrow at 475g, and momentum at .5600.

So I guess what I'm getting at here, is what does all this gobbeldy **** physics mathematical calculative mumbo jumbo translate into in regards to real world effectiveness? What would be a reasonable middle ground for a guy with a 27" draw? I get so much crap at my local pro shop when i talk about 425g arrows, 20% FOC, and off the shelf 2:1 ratio single bevel broadheads...and that's nowhere CLOSE to the kinds of numbers a lot of guys here suggest.


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## Matt H (Aug 23, 2014)

here's another question. i was wondering if anyone knows if there are hunting regulations on arrow weight? i see regs on draw weight, and broadheads. i don't know of any for deer but i'm curious about larger game like moose, elk, bear, and hogs if those meet different criteria


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## secretagentmann (Jul 6, 2012)

Cris Anderson said:


> So, here's a question. The heavy arrow I posted above has a momentum at 40yds of .5400ish. The lighter arrow is at .4800. What do you guys who prefer heavy arrows recommend for various game animals? There's plenty of KE charts...but nothing for momentum. I know full well that Dr. Ashby prefers an arrow weight of over 600 grains period, which will translate into 240fps or so out of my bow at my draw length, and .6400 momentum at 40yds. I'd like to keep my arrow speed up around 270-280fps preferably. Working backward that puts my arrow at 475g, and momentum at .5600.
> 
> So I guess what I'm getting at here, is what does all this gobbeldy **** physics mathematical calculative mumbo jumbo translate into in regards to real world effectiveness? What would be a reasonable middle ground for a guy with a 27" draw? I get so much crap at my local pro shop when i talk about 425g arrows, 20% FOC, and off the shelf 2:1 ratio single bevel broadheads...and that's nowhere CLOSE to the kinds of numbers a lot of guys here suggest.


Here's another question... 
Do you really get 240fps out of a trad bow? 
I haven't seen it all, but I've never heard of more than 200... That's using a reasonable (Mfc recommended gpp) arrow weight.
Now, if you're shooting a 70# bow with a 300gr arrow... OK. 
Be careful.


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## Beendare (Jan 31, 2006)

Cris Anderson said:


> So, here's a question. The heavy arrow I posted above has a momentum at 40yds of .5400ish. The lighter arrow is at .4800. What do you guys who prefer heavy arrows recommend for various game animals? There's plenty of KE charts...but nothing for momentum. I know full well that Dr. Ashby prefers an arrow weight of over 600 grains period, which will translate into 240fps or so out of my bow at my draw length, and .6400 momentum at 40yds. I'd like to keep my arrow speed up around 270-280fps preferably. Working backward that puts my arrow at 475g, and momentum at .5600.
> 
> So I guess what I'm getting at here, is what does all this gobbeldy **** physics mathematical calculative mumbo jumbo translate into in regards to real world effectiveness? What would be a reasonable middle ground for a guy with a 27" draw? I get so much crap at my local pro shop when i talk about 425g arrows, 20% FOC, and off the shelf 2:1 ratio single bevel broadheads...and that's nowhere CLOSE to the kinds of numbers a lot of guys here suggest.


 if there was one perfect arrow weight- we all would be shooting it and there would be no "heavy arrow" threads with hundreds of replies. GRIN


My take; everything works...a testament to the effectiveness of the bow and arrow- a very lethal weapon. Over the years I have migrated to heavier arrows as there have been some less than perfect shots I've either shot or seen with lighter arrows....that I am now convinced a heavier arrow would have had a little more umph to penetrate and make the difference. So i use and arrow/Bh styled for a less than perfect scenario.

IMO, you also have to think of your setup as a system- bow,arrow BH. An example would be my buddies 80# compound setup- he shoots a 550gr arrow with a mech head and almost never loses and animal. Now a guy shooting a loe energy trad bow must defer to a very efficient 2 blade or severely tapered 3 blade to get max lethal efficiency. the closer you get to "middle of the road" hard to say exactly what you need. 
I think a guy shooting a 400-500 gr arrow from a 45-50# trad bow still needs an efficient head. If he goes up to 600gr his MO numbers will go up but I haven't seen the lethality go up with the numbers..plus you lose trajectory. A guy shooting a 60# trad or compound bow has more options with arrow weight and BH efficiency. 

i have seen the ultra heavy arrows way outperform a much lighter arrow from the same bow on big critters like water buff- so there is no denying the performance...but that is a critter with overlapping 1 1/4" thick ribs, 12" of meat before you get to a rib and a total of 4 feet wide. I think we all agree this is not the norm for most of our hunts. I think a 450-525gr arrow for a 60-70# compound is a good compromise. I think a trad guy can go a bit heavier than that and be OK. Deer are pretty thin skinned and if thats all you hunt, no need to go real heavy- elk are a different story and they are much bigger and tougher than deer...so going heavier for elk is probably a good idea.


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## rattus58 (Jul 9, 2007)

Cris Anderson said:


> So, here's a question. The heavy arrow I posted above has a momentum at 40yds of .5400ish. The lighter arrow is at .4800. What do you guys who prefer heavy arrows recommend for various game animals? There's plenty of KE charts...but nothing for momentum. I know full well that Dr. Ashby prefers an arrow weight of over 600 grains period, which will translate into 240fps or so out of my bow at my draw length, and .6400 momentum at 40yds. I'd like to keep my arrow speed up around 270-280fps preferably. Working backward that puts my arrow at 475g, and momentum at .5600.
> 
> So I guess what I'm getting at here, is what does all this gobbeldy **** physics mathematical calculative mumbo jumbo translate into in regards to real world effectiveness? What would be a reasonable middle ground for a guy with a 27" draw? I get so much crap at my local pro shop when i talk about 425g arrows, 20% FOC, and off the shelf 2:1 ratio single bevel broadheads...and that's nowhere CLOSE to the kinds of numbers a lot of guys here suggest.


The momentum of my arrows are over .500 at the bottom end and all push the broadhead through flesh and bone at my range of shooting... around 20 to maybe 25 yards max, mostly less. FOC can make up for draw weight differences and arrow weight as well. A forward CG means that there is more weight forward dragging the arrow along and keeping "righted/aligned" to the arrows initial path of travel. Heavy arrows along their length accomplish the same phenomena just by virtue of their weight... and inertial guidance through the animal and bone. A momentum of .560 for anything here in my opinion will kill anything as long as the shot is sensible.

Aloha...


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## Cris Anderson (Oct 22, 2014)

secretagentmann said:


> Here's another question...
> Do you really get 240fps out of a trad bow?
> I haven't seen it all, but I've never heard of more than 200... That's using a reasonable (Mfc recommended gpp) arrow weight.
> Now, if you're shooting a 70# bow with a 300gr arrow... OK.
> Be careful.


And with this post...I JUST realized I was in the traditional section lol! My apologies gentlemen! I've been following along with intense interest, and had found this thread in the 'New Posts' section! I've chosen to shoot a 70lb compound for hunting...at least while i'm still on the steep part of the learning curve!



Beendare said:


> if there was one perfect arrow weight- we all would be shooting it and there would be no "heavy arrow" threads with hundreds of replies. GRIN


Right?! 



Beendare said:


> My take; everything works...a testament to the effectiveness of the bow and arrow- a very lethal weapon. Over the years I have migrated to heavier arrows as there have been some less than perfect shots I've either shot or seen with lighter arrows....that I am now convinced a heavier arrow would have had a little more umph to penetrate and make the difference. So i use and arrow/Bh styled for a less than perfect scenario.


This is the way I look at it also. As a newer hunter, I know my shot placement may not always be perfect. I also know that deer/elk/whatever aren't always going to just stand there broadside and let me snipe away at them. A heavier arrow in my opinion is at minimum more ethical, and most likely will more than once keep me from a long night chasing a wounded animal. That said, I'm also looking for reasonably decent speed as a crutch to mistakes in yardage estimates.



Beendare said:


> i have seen the ultra heavy arrows way outperform a much lighter arrow from the same bow on big critters like water buff- so there is no denying the performance...but that is a critter with overlapping 1 1/4" thick ribs, 12" of meat before you get to a rib and a total of 4 feet wide. I think we all agree this is not the norm for most of our hunts. I think a 450-525gr arrow for a 60-70# compound is a good compromise. I think a trad guy can go a bit heavier than that and be OK. Deer are pretty thin skinned and if thats all you hunt, no need to go real heavy- elk are a different story and they are much bigger and tougher than deer...so going heavier for elk is probably a good idea.


I had drawn up a 462g arrow, based on a 185g broadhead (2 blade, right hand single bevel, approximately 3:1 ratio...made by myself) using a 40g outsert, on Black Eagle 300 spine X-Impact shafts .231" diameter shafts. FOC was over 22%. With the bow above, it puts my initial velocity at 277fps, with 77.9lbs of KE, and .5684 momentum. At 40yds, the totals drop to 272fps, 75.81lbs of KE, and .5583 momentum. Just to share the information, time of flight to 45yds would be .53 seconds. By the 'KE charts'...that's more than enough energy to kill anything on this continent. I want to know whether it has a chance of killing anything on this continent, if the things turns quartering towards me in that half second, and I plow it in the shoulder blade, lol.



rattus58 said:


> The momentum of my arrows are over .500 at the bottom end and all push the broadhead through flesh and bone at my range of shooting... around 20 to maybe 25 yards max, mostly less. FOC can make up for draw weight differences and arrow weight as well. A forward CG means that there is more weight forward dragging the arrow along and keeping "righted/aligned" to the arrows initial path of travel. Heavy arrows along their length accomplish the same phenomena just by virtue of their weight... and inertial guidance through the animal and bone. A momentum of .560 for anything here in my opinion will kill anything as long as the shot is sensible.
> 
> Aloha...


Yes sir, 20% FOC is my minimum, even with a higher powered compound.


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## JParanee (Oct 13, 2009)

Cris 

Stick around its a very fun place


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## Stone Bridge (May 20, 2013)

JParanee said:


> Cris
> 
> Stick around its a very fun place


Only for the insane. 

Joe, they let me out today for some fresh air. I can hear the attendant calling me now, getting the jacket ready. Have to got to bed. Finally.


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## ozarksbuckslaye (Jul 24, 2008)

Matt H said:


> here's another question. i was wondering if anyone knows if there are hunting regulations on arrow weight? i see regs on draw weight, and broadheads. i don't know of any for deer but i'm curious about larger game like moose, elk, bear, and hogs if those meet different criteria


Not that I'm aware of. The conservation Commission's aren't known for being brainiacs but they're not completely brain dead either. Some even have enough sense to put a ban on expandable broadheads. Go figure.


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## weekender21 (Jan 27, 2012)

Cris, totally legit topic for compound and trad archery. After the arrow leaves the string we're all back to the same topic of KE vs. Momentum using the same math! I'm hoping to start hunting with my recurve (owned it for 5 years already) this season. Great discussion for all though.


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## secretagentmann (Jul 6, 2012)

lol chris, funny to me. i've done the same thing in a compound thread.
stick around in the trad sections. lots of good info here. maybe you'll shoot trad eventually. if you're looking for a challenge, this is it.


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## Boberau (Dec 15, 2009)

Cris Anderson said:


> So, here's a question. The heavy arrow I posted above has a momentum at 40yds of .5400ish. The lighter arrow is at .4800. What do you guys who prefer heavy arrows recommend for various game animals? There's plenty of KE charts...but nothing for momentum.


Hi Chris: You're pretty much correct. Going to Africa, I was very interested in this subject, especially since, as Rattus says, they have "standards" in Africa. I finally came across an article at http://www.africanarcher.com/ where the author discussed the differences between KE and momentum that made sense to me. He made a chart for African Planes game as follows (I hope it posts properly on this forum):
species min. momentum (in slugs)

Eland,Gemsbuck, Blue Wildebeest, Kudu 0.40
Red Hartebeest, Black Wildebeest, Tsessebe, Nyala 0.38 
Impala, Blesbuck, Bushbuck, reedbuck 0.35 
Springbuck, Mountain reedbuck and all small game 0.30 

Using this chart, I would think an Elk would require about 0.40 and a whitetail between 0.35 and 0.38. My 55# bow generated about 0.47 for Blue Wildebeest, which was just fine on my trip - even thought the South African KE standards suggested that I need at least a 65# bow.


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## Boberau (Dec 15, 2009)

As far as Joe, the original poster, is concerned: I think he should use what he likes. 

This is my experience: Yes, heavier arrows are quieter, but not enough to make any significant difference. I think I have found that heavier arrows have more penetration, after multiple experiments, but not enough to out weigh the differences in release from one arrow to the next (in other words, the difference is small). So, I wouldn't worry about heavy vs. light arrow for hunting most North American game species. And, arrow drop isn't a big issue at the distances we hunt - so that shouldn't be a major factor in your calculation. 

I would suggest that you make a serious attempt to stay away from shooting 33 yards at animals, if you can. For many, if not most, traditional bowhunters, our hunting success means getting close to our game. This year, I came to full draw on a whitetail deer that was about 35 yards. But, I let down, thinking it was further than I really should be shooting. Within 15 minutes, I had an 11 yard shot. Not only was the 11 yard shot more "doable," but that type of hunting (from the ground) is more exciting. 

Of course, that's just me. You need to make your own stories, and decisions. Good luck. I hope you enjoy the sport.


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## Beendare (Jan 31, 2006)

Cris Anderson said:


> I had drawn up a 462g arrow, based on a 185g broadhead (2 blade, right hand single bevel, approximately 3:1 ratio...made by myself) using a 40g outsert, on Black Eagle 300 spine X-Impact shafts .231" diameter shafts. FOC was over 22%. With the bow above, it puts my initial velocity at 277fps, with 77.9lbs of KE, and .5684 momentum.


My take, Excellent arrow from a 70# compound....assuming its tuned with BH's and FPs grouping together at distance


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## BarneySlayer (Feb 28, 2009)

Cris Anderson said:


> This is the way I look at it also. As a newer hunter, I know my shot placement may not always be perfect. I also know that deer/elk/whatever aren't always going to just stand there broadside and let me snipe away at them. A heavier arrow in my opinion is at minimum more ethical, and most likely will more than once keep me from a long night chasing a wounded animal. That said, I'm also looking for reasonably decent speed as a crutch to mistakes in yardage estimates.


Two things...

As a fairly inexperienced hunter, my limited recent experience has been eye opening. 

First, that no matter what you do, there are no sure shots. If you take the shot, you risk taking a shot that won't work out. Not only can we screw up, but animals move. Whatever your comfortable range is for inanimate animals, shorten it significantly if you've got ethical concerns, or don't want to be crawling around in the middle of the night.

Secondly, if you have any notion that yardage estimates might come into play, just go ahead and bring a range finder with you. If you're in a fixed location, range different distances, and memorize them. If you're stalking, range distances from time to time to get a handle on how far is what. Even if you have to improvise, 10 vs. 20 vs. 30 will be fresher in your mind.

As far as either KE or momentum, so long as you're shooting something in any of the Americas, I'd be more concerned with not hitting the big bones than your arrow stopping. Compared to the traditional bows, that supposedly can work just fine with larger game, you're shooting a cannon.


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## Cris Anderson (Oct 22, 2014)

Beendare said:


> My take, Excellent arrow from a 70# compound....assuming its tuned with BH's and FPs grouping together at distance


Yes, tuning is critical to any bow/arrow combination from my limited understanding. I'm not one to do things halfway lol. If I build a 10 second car, it'll be tuned to run 9.99's. Same goes for my bow/arrows . 

Earlier this evening I drew up another arrow at 550g. With a faster bow I've been considering (APA M5), it only lost about 12fps (265fps vs 277) off the bow, and gained everywhere else.

I have a feeling I'm going to be spending more money on studying/building arrows than I ever will on my bow.../sigh!



BarneySlayer said:


> Two things...
> 
> As a fairly inexperienced hunter, my limited recent experience has been eye opening.
> 
> ...


I agree across the board. There's always that one arrow that flies off into some weird spot on the target for some unknown reason...plus like we both said, they don't just stand there broadside looking at you waiting for the arrow very often. The range/forgiveness thing is just a nice cushion for that stuff. At 265fps initial velocity, a +/-5yd misjudgment from 35/40/45yds is a 4"/0/-5.5"" from point of aim with the 40yd pin. That isn't horrible, but couple it with a moving and/or alerted deer, and who knows where you'd hit. Here in Arizona, shots tend to be longer than back east from my understanding, and a 40yd shot is probably typical. The 550g, 26%FOC arrow might plow through two deer side by side though, lol. 

Either way I intend to spend some time this winter/spring (whenever I finally decide on and get my bow) up north though, in whatever unit I decide to hunt. Spot/stalk stumping (or squirrel/rabbit hunting!), or stumping from existing permanent tree stands...with various arrow mock ups will probably go a long way towards easing my concerns, as well as familiarizing myself with my equipment under the circumstances it will be used in. I figure anything less will be a disservice to myself, my investment, and to the elk/deer I'll be shooting at next hunting season, at the least.

Honestly, right now...it's all just academic. I'm still waiting to choose my bow, and will have a whole year of waiting till I can go hunt deer...so I'm obsessing over the things I can do in the meantime .


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## Beendare (Jan 31, 2006)

*bone shot*



Cris Anderson said:


> I had drawn up a 462g arrow, based on a 185g broadhead (2 blade, right hand single bevel, approximately 3:1 ratio...made by myself) using a 40g outsert, on Black Eagle 300 ............... I want to know whether it has a chance of killing anything on this continent, if the things turns quartering towards me in that half second, and I plow it in the shoulder blade, lol.


Cris,
The arrow you described with the right head will blow through most everything except maybe a dead on shot on an elks leg bone- should get through a deers leg.
I've shot elk through both shoulder blades-[ compound bow 70#] complete pass [scapula] and the arrow went so far down hill I never found it. Of course it wasn't on purpose, the bull came running in to my buddy calling and he almost ran by me, slightly down hill, he turned slightly towards me when I swung my bow. I caught him higher than I wanted on the snap shot- about a 460gr arrow back then,Axis 300's, magnus Snuffer ss head. The arrow went through him so fast he stopped and just stared- for the count of 8....then fell over. It helped that my buddy was just screaming on the bugle. I've broken big midwest whitetail leg bones with similar setup. Now with a 50# trad bow....its probably a different story.
Again, shot with a compound on the trad forum...but to your question


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## Cris Anderson (Oct 22, 2014)

Beendare said:


> Cris,
> The arrow you described with the right head will blow through most everything except maybe a dead on shot on an elks leg bone- should get through a deers leg.
> I've shot elk through both shoulder blades-[ compound bow 70#] complete pass [scapula] and the arrow went so far down hill I never found it. Of course it wasn't on purpose, the bull came running in to my buddy calling and he almost ran by me, slightly down hill, he turned slightly towards me when I swung my bow. I caught him higher than I wanted on the snap shot- about a 460gr arrow back then,Axis 300's, magnus Snuffer ss head. The arrow went through him so fast he stopped and just stared- for the count of 8....then fell over. It helped that my buddy was just screaming on the bugle. I've broken big midwest whitetail leg bones with similar setup. Now with a 50# trad bow....its probably a different story.
> Again, shot with a compound on the trad forum...but to your question
> View attachment 2097618


That sounds like a perfect place for me to start then...thank you. The head I'm looking at making will be a single bevel, somewhere between 2.75" and 3" of cutting edge length, with just the slightest of parabolic shaping on each cutting edge. Most likely 1" to 1.25" cut width. I know there's plenty of packaged broadheads out there that will do the job...but I want mine to be personal. Plus, as a full time bladesmith, it's just one more thing that will advertise my work for me. 

I just have to find a manufacturer who will sell me ferrules with no blades, lol.


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## Beendare (Jan 31, 2006)

What about taking some existing Field points, modifying and welding them to your blade?


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## Cris Anderson (Oct 22, 2014)

Beendare said:


> What about taking some existing Field points, modifying and welding them to your blade?


I thought about that...but welding high carbon to mild can be a pain, and the steel I'm using is 1% carbon. Plus, for the work to be quality they would need tigged. Add to that that hardening them after they'd been welded (welding after hardening would ruin the temper) would probably rip the blades right off the field point lol.

I found replacement German Kinetic ferrules for $6.50 each...plus $5.50 per 10 screws (each head takes 2 screws). Kinda steep, but since I should only need 6, I guess it's not that bad. MUCH cheaper than the full heads with blades!!

http://www.southshorearcherysupply.com/german-kinetic-replacement-ferule-large-p-52087.html


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## dragonheart II (Aug 20, 2010)

Shoot heavy. 

Quit worrying about speed.

Use a rangefinder calibrated to your pins if you are concerned about shooting longer shots. 

Penetration=recovery of animal. 

Plan for the worst case scenario hitting bone.

Look at this,


http://www.alaskabowhunting.com/Webpage.aspx?WebpageId=131


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## Cris Anderson (Oct 22, 2014)

dragonheart II said:


> Shoot heavy.
> 
> Quit worrying about speed.
> 
> ...


I think the 450-550g arrows I'm most likely going to build are reasonably heavy....and I don't think a preferred 265fps minimum is going crazy about speed. I know it's 100fps more than many traditional bows, but at the same time there's reasons right now that I'm shooting a compound and not a trad bow...and one of them is absolutely speed. Hell, most guys that shoot compounds aren't satisfied unless their arrows are above 300fps lol.

Eventually I may join the 650g plus club...but for now, I think I need all of the cushion for shot placement I can get...with enough momentum and FOC% to punch through whatever obstacles a bad shot might put in my way.

And again...right now it may seem like I'm overly concerned with speed, but once I can get out and start doing some shooting to gain some confidence (other than at a hay bale) it will probably all settle down. I don't know enough at this point to know WHAT to really be concerned with, so I'm just trying to cover every base I can.


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## Cris Anderson (Oct 22, 2014)

Oh! Those videos were freaking amazing by the way!

Just thought I'd add that


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## dragonheart II (Aug 20, 2010)

Cris,

I am not much of a fan of the outhouse channel, but I am amazed sometimes at what I see. I am amazed to see a hunter shooting a 70 pound modern cam compound bow that could be generating tremendous energy, only to get very little penetration on a whitetail deer. Why? Lightweight arrows and fast. Less momentum. Less penetrating power. 

Dont get me wrong I want as quick a bow that I can shoot accurately under actual hunting conditions. I like a quick bow too. But in every recovering rate study I have ever looked at, penetration and getting all the way thru leads to recovery of the animal. This has also proven itself to me in my lifetime of hunting with a bow and arrow. It is important to work to get a setup that works even when the arrow placement is not perfect. Bowhunting is meant to be a close range endeavor. There are those rare situations that warrant shots at long range, but most shots are going to be close. 

I am shooting a 60# recurve with a 605 grain arrow tuned to fly true and have shot pass-thru a sow hog and a buck. ALL the way thru. 

I only have a 27" draw, so not tons of speed, but the momentum to get all the way there. If hunting is your game, then you will not go wrong with a heavier arrow. Put as much weight as possible on the front of the arrow. The bow will be quieter, more forgiving, and give adequate speed for the close range shots.


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## Cris Anderson (Oct 22, 2014)

dragonheart II said:


> Cris,
> 
> I am not much of a fan of the outhouse channel, but I am amazed sometimes at what I see. I am amazed to see a hunter shooting a 70 pound modern cam compound bow that could be generating tremendous energy, only to get very little penetration on a whitetail deer. Why? Lightweight arrows and fast. Less momentum. Less penetrating power.
> 
> ...


I understand completely...and agree. Here in AZ though, average shots in units within a reasonable range to me are between 30-70yds from what I've read. Lots of open country around here, not a lot of trees, lol. This is all theoretical for now, but that's why Im trying to hold to about 265fps for my bottom window. The last thing I want to do is go out on my first hunt, and miss by a mile due to a misjudgment of range or a moving deer.

Here's an interesting comparison post I made today for a guy on a different thread (similar topic):



Cris Anderson said:


> 2014 Xpedition Xcentric, 70lbs, 27" draw length. Holding the arrow on a set 10yd pin.
> 
> 540g arrow - 257fps
> 10yds, 0
> ...


The 540g arrow is a little slower out of that bow than I think I would like...but as I mentioned before, until I get out there and see how I'm shooting in the field, it's all just theory. In the end as my skills develop...I'm sure I'll be leaning towards heavier and heavier arrows...which is kind of funny, because at my local pro shop I'm already catching grief for even bringing it up .


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## Still mustang (Jan 22, 2014)

This past Friday I shot a older doe. 51# recurve, Tradtech Carbon/Wood limbs, 28"AMO draw length, which measures 51#'s. Anyway, pure broadside shot at 18yrs. Hit was about 3"behind her heart a little under halfway up, not the best hit but it will get the job done. Arrow went all the way to the fletching and stopped. She broke the arrow as she wheeled and bolted in to the woods, broadhead side arrow must have hit a tree and snapped being that it was lodged between both sides of her rib cage. Fletching end of arrow was lying about 35yrds from the hit. Did not find my broadhead. Arrow weighs 410 grians and Zwickey Eskilite 2-blade was shaving sharp. 

I haven't shot a lot of deer but I'm surprised the arrow did not completely pass thru and be laying on the dirt behind her.
It has me reconsidering my relatively light arrow setup.


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