# Heavy arrow question



## Tater1985 (Apr 28, 2008)

Bushwackr said:


> Hello I normally shoot a 446 grain arrow that comes out of my ally at 282fps. I have some arrows that come out to a whopping 635 grains. can anyone give me an idea what I should see for fps , and will I gain or loose in kenetic energy because of the arrow weight. Thanks


With your current setup and 282 fps you are getting about 78.8 ft-lbs of KE and 0.5584 slug-ft/sec of momentum.

Changing nothing but arrow weight to 635gr will put you in the neighborhood of . . . . . 

219 fps
67.6 ft-lbs of KE
0.6175 slug-ft/sec of momentum

Even though your KE dropped, I am a firm believer that this significant jump in momentum will show a drastic improvement in overall penetration, especially if you hit heavy bone. I assume you are going after something rather large?


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## Nitroboy (Jan 15, 2006)

Tater1985 said:


> With your current setup and 282 fps you are getting about 78.8 ft-lbs of KE and 0.5584 slug-ft/sec of momentum.
> 
> Changing nothing but arrow weight to 635gr will put you in the neighborhood of . . . . .
> 
> ...


Finally a smart person that thinks the same way I do:teeth:, I have arguement after arguement with people saying that a super fast light weight arrow will over penetrate a slower but heavier arrow and I say BS and explain to them the momentum thing but they just can't grasp the concept I don't guess, You see a longbow shooting 140fps with a 650gr arrow will shoot clean through any North American game animal, not because of KE but because of momentum, Its alot harder to stop a loaded Peterbuilt than it is a Mazda Miata


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## Rockyhud (Sep 17, 2008)

*Absolutely correct*

Tator and Nitro are correct - momentum, not KE, is what increases penetration potential. Besides all the testing done by Dr Ed Ashby, Eastman's Bowhunting Journal published a couple of very good tech articles in the Jan-Feb 2010 issue; one addressing KE versus momentum and the other addressing higher FOC titled "Bowhunting's Biggest Lie" and "Advanced Tweaks For Your F.O.C". They were written by Darin Cooper, their relatively new Technical Editor. Besides being a highly skilled competition archer, for 10 years Darin was a Sr. Product Engineer for Hoyt, being personally responsible for the design of their patented Cam & 1/2 systems and other important components. He knows his stuff.

In the article about momentum he proves out how a 525 gr arrow shot from a 60# bow penetrates deeper than a 425 gr arrow shot from an 80# bow, all due to the higher mass and momentum of the heavier arrow. Darin's real world tests basically prove out Dr Ed Ashby's own theories and testing. His article on higher FOC is also very informative, again supporting Ashby's testing.

Since investigating this more myself I've been convinced to do the same. I have a dozen Maxima 350 shafts (8.2 gr/in) that weigh 390 gr with 100 gr tips that I've chrono'd consistently at 290 fps. I recently bought 6 Gold Tip Big Game 100+ shafts (10.6 gr/in) that weigh 555 gr with 200 gr tips that I've chrono'd at 249-250 consistently. Each time I've shot these arrows into my field point target the heavier arrows have penetrated deeper than the lighter ones every time. I have never had the Maximas so much as produce a bulge on the backside but the Gold Tips do so regularly, to the point of almost penetrating clear through.

My new elk and other BIG game arrows are now these Gold Tip shafts tipped with Grizzly El Grande 2-blade single bevel broadheads that weigh about 215 gr - total arrow weight being 570 gr. I'll still use the Maxima shafts with my 100 gr Magnus Stinger 4-blade broadheads but these will also have 50 gr weights screwed into the back of the inserts to increase the mass and FOC. These will be for pronghorn and similar sized and smaller game.


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## Tater1985 (Apr 28, 2008)

Rockyhud said:


> My new elk and other BIG game arrows are now these Gold Tip shafts tipped with Grizzly El Grande 2-blade single bevel broadheads that weigh about 215 gr - total arrow weight being 570 gr. I'll still use the Maxima shafts with my 100 gr Magnus Stinger 4-blade broadheads but these will also have 50 gr weights screwed into the back of the inserts to increase the mass and FOC. These will be for pronghorn and similar sized and smaller game.


I too am utilizing the 50gr insert weights in my hunting arrows and am building another set for a customer. These 50gr weights allow you to do two things that I would suggest impove both arrow flight and penetration:

1) Allows you to shoot a stiffer spined arrow that weighs more, that you could never shoot with just 100gr up front.

2) Weakens the spine of the arrow while also significantly improving your FOC.


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## SonnyThomas (Sep 10, 2006)

Nitroboy said:


> Finally a smart person that thinks the same way I do:teeth:, I have arguement after arguement with people saying that a super fast light weight arrow will over penetrate a slower but heavier arrow and I say BS and explain to them the momentum thing but they just can't grasp the concept I don't guess, You see a longbow shooting 140fps with a 650gr arrow will shoot clean through any North American game animal, not because of KE but because of momentum, Its alot harder to stop a loaded Peterbuilt than it is a Mazda Miata





Rockyhud said:


> Tator and Nitro are correct - momentum, not KE, is what increases penetration potential. Besides all the testing done by Dr Ed Ashby, Eastman's Bowhunting Journal published a couple of very good tech articles in the Jan-Feb 2010 issue; one addressing KE versus momentum and the other addressing higher FOC titled "Bowhunting's Biggest Lie" and "Advanced Tweaks For Your F.O.C". They were written by Darin Cooper, their relatively new Technical Editor. Besides being a highly skilled competition archer, for 10 years Darin was a Sr. Product Engineer for Hoyt, being personally responsible for the design of their patented Cam & 1/2 systems and other important components. He knows his stuff.
> 
> In the article about momentum he proves out how a 525 gr arrow shot from a 60# bow penetrates deeper than a 425 gr arrow shot from an 80# bow, all due to the higher mass and momentum of the heavier arrow. Darin's real world tests basically prove out Dr Ed Ashby's own theories and testing. His article on higher FOC is also very informative, again supporting Ashby's testing.


Not that I disagree with either of the above, but the point is useless as the intended game should be included in setting one's hunting rig. You don't need a 5 pound hammer to drive a thumb tack.
Bottom line; Arrow placement is paramount.


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## 2-dogs (Aug 31, 2009)

*Heavier arrow.*

I agree with everyone above and I also shoot a heavy head 170 grain. I think its alot more forgiving, it want jump off near as far on a bad release and what some people don't understand it really doesn't drop off that much more out to 40 yds. then a lighter setup, its just slower getting there. My arrow shoots like darts out to 60 yds.


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## Nitroboy (Jan 15, 2006)

SonnyThomas said:


> Not that I disagree with either of the above, but the point is useless as the intended game should be included in setting one's hunting rig. You don't need a 5 pound hammer to drive a thumb tack.
> Bottom line; *Arrow placement is paramount*.


True, *BUT* I have been bowhunting for nearly 20 years and you don't always get a perfect shot or release a perfect arrow everytime you shoot at a game animal, Where humans and anything bad that can happen usually will happen when we practice all summer calm and collect and then fall rolls around and 'Ol Wally Moosehead brother of 'Ol Mossy Horns steps out and gets our adreneline pumping and buck fever takes over and we happen to torque the grip and pull the shot alittle off hitting a shoulder bone, Nice heavy slow arrow, would bust right through getting both lungs, fast light arrow probly/maybe got just one lung, may get him may not, I'll go with the 5lb hammer and drive that thumb tack threw the wall, lol

Atleast thats me, Cause I still get shook-up bad when I decide to take an 'ol doe for some table fare, Thats why I bowhunt


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## td051 (Jan 14, 2007)

Bushwackr,
May I ask your reasoning for shooting such a heavy arrow? Are you going after dangerious game?

I agree that more mass equals better penatration, but it's my belief that it has a negative effect when going to heavy, but really depends what your doing.

I have been hunting with a Ally since they came out, but may be replaced this year. There is nothing with hoof's or paws in North America that that bow will not pass through with proper arrow flight, razor sharp broad heads and proper shot placement. Personally, I sacrafice weight for speed, but let me explain.

First I am not hung up on speed for a hunting bow. I just want to have the benifit of it for yardage estimation/error. I don't know your set up but a 400-450 grain is perfect for me. Still get good speed and enough weight. If I'm off on my yardage I still have the utmost cofidence on my shot even with wary game. Everyone knows a broad head kills by cutting not shock. Now if your sitting in a blind over a water hole shooting 20 yards in Africa, that's another story.


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## Bushwackr (Jul 10, 2008)

Thanks all 

td051
I guess its not so called dangerous game, but they are dangerous enough to me. A friend and I are goin to hunt wild boar. I was goin to try them on whitetail this bow season first. I guess I am just trying to find out how to make as much pass thru punch as possible. I am goin to use 100gr magnus stingers, and sabermaxx broadheads. I figured the deer would give me some insight in to how I need to approach these things. I thought that I could see how I need to adjust for the slower arrow speed than my 450 grainers arrows give me. 

Or am I doing this for nothing but a learning tool?


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## honda foreman (Feb 17, 2010)

i agree


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## SonnyThomas (Sep 10, 2006)

SonnyThomas said:


> Not that I disagree with either of the above, but the point is useless as the intended game should be included in setting one's hunting rig. You don't need a 5 pound hammer to drive a thumb tack.
> Bottom line; Arrow placement is paramount.





Nitroboy said:


> True, *BUT* I have been bowhunting for nearly 20 years and you don't always get a perfect shot or release a perfect arrow everytime you shoot at a game animal, Where humans and anything bad that can happen usually will happen when we practice all summer calm and collect and then fall rolls around and 'Ol Wally Moosehead brother of 'Ol Mossy Horns steps out and gets our adreneline pumping and buck fever takes over and we happen to torque the grip and pull the shot alittle off hitting a shoulder bone, Nice heavy slow arrow, would bust right through getting both lungs, fast light arrow probly/maybe got just one lung, may get him may not, I'll go with the 5lb hammer and drive that thumb tack threw the wall, lol
> 
> Atleast thats me, Cause I still get shook-up bad when I decide to take an 'ol doe for some table fare, Thats why I bowhunt


First, the originator is launching a 446 gr at 282 fps, good for 78 ft lbs of KE. This can knock over the largest moose or grizzly. Again, proper arrow placement is paramount. A 446 gr arrow is not rated on the low side for arrow weight, more like upper mid weight. AMO for arrow weight is still 540 grs. Next, my 380 gr arrow launched at 270 fps. blows through a deer like paper. I've thought I've missed because the arrow went through so fast and this with mechanical broadheads. I've taken 3 headon shots where the arrows buried fully in the deer twice and once leaving on the vanes sticky out. In the past 10 years the same weight arrow/bow has collected 32 deer with out fail.

Bushwackr, your present rig will get the job done on wild boars. I didn't notice your use of broadhead. Use a super sharp cut on contact fixed blade broadhead. The Shield covering a boars shoulder area is tough as in real tough. If you opt for the heavier arrow I don't see a problem.


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## Bushwackr (Jul 10, 2008)

OK thank you everyone. I will give them a try, but I wont be afraid to use my current setup. I have never had a shot on a deer that wasnt a pass thru. I would like to think that I would see the same performance on a hog. Or am I mistaken? Not trying to get off the subject.


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## Nitroboy (Jan 15, 2006)

A full grown hog with the cartilage armour they tote around the area your going to want your arrow to go will most likely stop the arrow you have now, you'll get a good penetrating shot and maybe break through the off side but doubt you'll get a full blown pass thru,( _I have shot a few good sized hogs and when skinning them find that the armour plating they have is over an inch thick, A Easton Axis 475gr arrow pushed by a 77lb DW bow wouldn't go through it_) again I'll say on a full grown hog, now you go to the heavy arrow with a 2 blade magnus BH and you'll not have to worry about a pass thru, Oh yeah and dangerous game?...... Hell Yes they are dangerous, if your in a stand no they aren't but when your on the ground eye to eye they are very dangerous animals


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## ramboarhunter (Jun 5, 2006)

*Fps & ke*



Tater1985 said:


> With your current setup and 282 fps you are getting about 78.8 ft-lbs of KE and 0.5584 slug-ft/sec of momentum.
> 
> Changing nothing but arrow weight to 635gr will put you in the neighborhood of . . . . .
> 
> ...


Tater,
Where did you find the formula to calculate monentum. I have looked everywhere for it.
According to my figures he should be getting somewhere between 236 and 240 FPS and somewhat over 80ft/lbs of KE.
My calculations have been pretty darn close when checking speed thru a chrono.
Charlie


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## Roskoes (Jun 17, 2007)

ALthough I had not planned on using my speed bow last fall for elk, it just kinda worked out that way. I shot an 800 lb. bull elk at 46 yards with a 314 grain arrow - going 326 fps. Got a pass through. With a Rocket Wolverine expandable no less.

My regular elk bow shoots a considerably heavier arrow, but it was amazing how well the light fast shaft penetrated.


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## TMan51 (Jan 25, 2004)

SonnyThomas said:


> Not that I disagree with either of the above, but the point is useless as the intended game should be included in setting one's hunting rig. You don't need a 5 pound hammer to drive a thumb tack.
> Bottom line; Arrow placement is paramount.


Sonny, you're getting mild mannered with age.

I keep telling myself that momentum is more important than kinetic energy, but since I dropped down to 60lb bows, and lighter arrows I'm starting to wonder about that.

I have had a long string of "deer dead in sight of the stand", it's run several years in a row now. I shoot most deer with arrows in the 320-370gr weight range, at speeds in the 275-300fps range. I've found that faster arrows seem to consistantly kill faster than slower arrows. By a lot.

The difference is likely due to the fact that I'm better at placing my shots than I was 30 years ago shooting 70lb bows, with 2219's.


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## Tater1985 (Apr 28, 2008)

ramboarhunter said:


> Tater,
> Where did you find the formula to calculate monentum. I have looked everywhere for it.
> According to my figures he should be getting somewhere between 236 and 240 FPS and somewhat over 80ft/lbs of KE.
> My calculations have been pretty darn close when checking speed thru a chrono.
> Charlie


Don't remember where I found it. Did some research a while back when I was building a spreadsheet to calculate all of that. My spreadsheet is available to download here on AT.


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## dmr (Sep 9, 2009)

Tater1985 said:


> With your current setup and 282 fps you are getting about 78.8 ft-lbs of KE and 0.5584 slug-ft/sec of momentum.
> 
> Changing nothing but arrow weight to 635gr will put you in the neighborhood of . . . . .
> 
> ...


Tater,
I think you may have a bug in your calculation. Generally speaking, shooting a heavier arrow will yeild increased KE b/c in most (all?) cases a bow is more efficient shooting heavier arrows. Your calculation assumes the bow becomes less efficient with the 635 gr. arrow. 

At worst case (assuming no efficiency gain ==> so KE=78.78 ft-lbs) the speed with a 635 gr. arrow sould be between 236 and 237 fps. My guess is it would be somewhere closer to 240 fps if measured on a chrono.


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## konrad (Mar 29, 2009)

My rig: 61 pound draw weight. 27 inch draw length, 29 inch arrow (2413 alloy) weighing 490 grains, 16%FOC and chronographs between 235 and 240 fps. People always shake their heads at the range until they see the targets. Speed is secondary to my pursuit of accuracy. The bow is dead quiet and would shoot “Robin Hoods” at 50 yards all day…if I was a better archer. 

I would not feel under gunned when looking for bacon. I wish they were here (Don’t let the local farmers hear I said that!). My two-blade Magnus Stinger is as accurate as the field point, quiet in flight and penetration has never been an issue.

Shot placement comes first. Lethality runs hand in hand with accuracy.
My confidence comes from seeing results and knowing if I do my job, there will be blood.

For hogs I still think I would feel more comfortable in a stand…off the ground! Ever seen a 240 pound chicken?

For those who are interested in the Ashby data, he has proven the weight of 600 grains to be the tipping point for 100% bone breaching (assuming a well made, two edged point, stiff shaft and smooth transitioning ferrule to shaft). The tests were using Asian Buffalo shoulder blades.

I don't know the slug feet of this ammo but they want to go through my Yellow Jacket bag target pretty quick if I don't rotate aiming points.


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