# Grains per pound



## WHD 32519 (Oct 17, 2008)

I know that arrows can be too light for the bow, but is there a limit to how many grains per pound before the efficiency of the bow and arrow combination is adversely affected? 

Is there a point of maximum efficiency?

Good shooting,
Chris


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## sswv (Jul 3, 2005)

*gpp*

from all I've read and heard the "general rule of thumb" is 10gpp for hunting.

I think most test on trad bows are done at 9.0gpp


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## longbowhunter (Mar 5, 2004)

What SSWV said. Any arrows less than 8 GPP and most bowyers warranty's will be void.


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## katman (Jun 5, 2006)

From what I have read efficiency goes up as arrow weight increases, what is the upper limit? have not got a clue. However as arrow weight goes up so does your arc of the arrow so to heavy and accuracy suffers. General rule I follow for hunting is shoot the heaviest arrow I can accurately shoot at my hunting ranges. 8-10 gpp is the most commonly sited range but have read of some shooting 14gpp.


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## Bender (Dec 6, 2006)

Bob Lee bows are warrantied down to 6 gpp. But that would be considered a liitle light for hunting! Efficiency and KE out of the bow rises as arrow weight rises, but velocity begins to drop dramatically after 10 or 11 gpp.


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## BLACK WOLF (Aug 26, 2005)

I could be wrong but I would bet there's a simple equation that can approximate the best arrow weight for a certain bow for optimum KE and/or MO.

The key is to know how many grains reduces or increases an arrow's speed by 1 fps. I think it's some where around 8 or 9 grains.

First shoot your bow through a chronograph and write down your arrow's total weight and it's speed.

Than find it's KE and MO.

Let's say it was 10g. for every 1 fps. and you shot your bow through a chrono and got 185fps. with a 550g. arrow.

Say you want to approximate what the bow's KE and MO will be with a 650g. arrow. Based on your arrow speed decreasing 1fps. for every 10g. your arrow will be going approx. 175fps. Now run those numbers through the KE and MO equations and I think you will get the idea.

I have no clue if that's right or wrong but it's the only way I can think of how to find out at what point you end up with diminishing returns.

Ray


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## LBR (Jan 1, 2004)

Too many variables--it's going to be different depending on the bow, archer, string, etc.

Chad


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## WHD 32519 (Oct 17, 2008)

I really didn’t mean this to be a trick question. How heavy an arrow should be is as important as selecting the spine rating. 

The answers are fairly simple, the explanation is not. The two major players are the bow’s maximum string speed and the power curve of the bow from release to launching the arrow. The kinetic energy formula is also involved. You must also know that energy can only be transferred from the bow to the arrow by acceleration of the arrow, if that acceleration stops so does the transfer of energy.

If an arrow is too light it will accelerate to the max string speed (approx.) and can’t go any faster even though there’s still plenty of transferable energy left. This unused energy must be absorbed by the bow usually resulting in hand shock, vibration and excessive noise. Quiet bows are good. 

An arrow should be heavy enough to absorb 100% of the transferable energy from the bow. The minimum is when the bow runs out of enough energy to continue the acceleration at the exact point that the arrow leaves the string. While there is a minimum gpp, it has a nice working range.

When an arrow is too heavy the arrow will reach a point where the energy required to continue accelerating the arrow exceeds the energy left in the bows’ power curve at that point in the travel. The string will continue to push the arrow but without acceleration there isn’t any transfer of energy. Arrow speed drops big time.

The exact gpp numbers depend on the design and material used in the construction of the bow. I’ve shot one #60 recurve that could shoot a 500 grain arrow at 150fps then shot the same arrow out of another #60 pound recurve at 200fps. Bows are not all alike so exact numbers are impossible to give.

A given bow has a maximum amount transferable energy, all the arrows qualifying in the maximum efficiency range will have about the same KE and the same basic penetration, heavier arrows don’t have an advantage. So you have to look to other factors if you need to improve penetration. 

I tuned my two recurves 25+years ago the old fashioned way, how they shoot out of the bow. Smooth, good groupings and quiet, amazing but it works, all of the arrows are just under 8gpp. The Howatt Hunter can shoot a 650 grain arrow at just over 205fps and is very quiet, can’t ask for more than that.

I started this thread because I’ve read of several people using high gpp arrows, the last time I shot a bow with 12gpp arrows the performance sucked, so I just wanted to raise awareness.

I would always rather be the student than the teacher.

Good shooting,
Chris


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## ncsturkey (Oct 18, 2004)

"The Howatt Hunter can shoot a 650 grain arrow at just over 205fps and is very quiet, can’t ask for more than that."

That is exceptional performance. Tell more about the bow. i.e. poundage length, limb construction, etc. 

Thanks


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## WHD 32519 (Oct 17, 2008)

It is a 1983 #80 that is #87 pounds at my draw of 29.5. It is 62 inches. Viper 1 knows a lot more about the construction than I do. Mine is not the fastest Hunter, the other one was custom built #90 being shot at 31" and went about 210fps.

Good shooting, 
Chris


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## katman (Jun 5, 2006)

OK WHD, so when you get to 100% of transferable energy with a given weight arrow you have reached the maximum KE an arrow will achieve? Now if you continue to raise arrow weight doesn't KE increase? Back when I use to calculate KE and MO for arows from 8-14 gpp that I shot these values increased as arrow mass increased.

Don't take this wrong but you seem to be more interested in speed(performance in your words). Not neccesarily a bad thing but those who can handle the trajectory challenge of a heavier slower arrow will have more KE. I am certainly not a physics or engineer guru so just trying to understand your thoughts, and scraping the cobwebs off college physics many years ago.


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## BLACK WOLF (Aug 26, 2005)

katman said:


> Back when I use to calculate KE and MO for arows from 8-14 gpp that I shot these values increased as arrow mass increased.


Did you calculate in the slower speeds with the increase in arrow weight?

Ray


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## WHD 32519 (Oct 17, 2008)

Katman,

Once you are shooting within the maximum efficiency range whether you choose to shoot a lighter arrow or a heavier arrow is up to you. KE will not change, that, I believe, falls under the conservation of energy rule, the arrow can not have more energy than the bow has.

I set my bows up to shoot well, speed never had anything to do with it, however having a fast bow is not a bad thing.

Good shooting,
Chris


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## Bender (Dec 6, 2006)

WHD you said "Once you are shooting within the maximum efficiency range whether you choose to shoot a lighter arrow or a heavier arrow is up to you. KE will not change,"
Sorry, not true. KE drops as arrow mass goes down 
For every action there is an equal and opposite reaction. Upon release the string pushes the arrow forward, the riser is pressed back into the hand. Light arrows lead to unused energy, hand shock, and the bow attempting to leap forward at the end of the power stroke. The closest we could come to 100% effeciency would be with an arrow that weighed exactly the same as the bow itself. Equal and opposite reactions. Max KE, rather poor performance.


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## WHD 32519 (Oct 17, 2008)

Bender,

Within the max efficiency range, as the mass goes up the speed goes down, as the mass goes down the speed goes up. KE remains the same.

As for the second point: I used the term "transferable energy." Not all of the bows' energy is transferable to the arrow. I said that shooting arrows that are too light would do exactly as you said, so we totally agree.

Good shooting,
Chris


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## petew (Nov 14, 2004)

www.bowjackson.com has some very good calculators . Chrono the bow in question with several weight arrows and run the numbers.
KE/ MOM/ drop and speed are all shown out to 100yards. Then make informed decisions.
Personaly I like light and very fast arrows for 3D 5 to 6gr/# and very heavy slower arrows for hunting.14 to 16gr/#.

Pete


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## Bender (Dec 6, 2006)

Again sorry WHD. Formula is KE=(1/2)(M)(V)(V) There is not a one to one relation between mass and velocity. Velocity is squared. There is not some special spot where you get to alter one variable without also altering KE.
I will admit that as arrow mass goes up the difference becomes smaller as efficiency increases. It reaches the point where the instuments that most of us have at our disposal can not measure the difference. None the less it does exist.


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## Wolf among dogs (Jan 5, 2007)

9-11...depends on the bow and the arrow too !


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## WHD 32519 (Oct 17, 2008)

Most of us don’t have a chrono to use but I think there is a way to know whether you are using arrows that are too light or too heavy.

KE determines penetration, more KE, more penetration. If an arrow is too light then it has less KE and less penetration, if an arrow is too heavy then it also has less KE and less penetration. Assuming that a given target has consistent resistance then measuring the penetration would be a way of referencing the KE. 

You will need a bunch of arrows ranging from perhaps 6gpp to 14gpp and draw a reference ring say 20 inches from the point. Shoot the arrows into the target, tight groups might be anti-productive. Measure the distance from the reference ring to the surface of the target and subtract from the 20 inch (point to reference ring) distance. Arrows of the same gpp should all penetrate about the same. You should notice that the middle range gpp arrows should be about the same and have the deepest penetration.

Arrows that are too light or too heavy should not penetrate much as the arrows that are in the max efficiency range.

I personally think that arrows that are toward the heavy end may have a little more KE, but the important point is that arrows can be too heavy. The bottom line is that the arrows need to shoot well and the bow needs to be quiet.

What prompts me to point all of this out is that it seems almost everyone stresses the use of heavy arrows including some that have to be too heavy for the bow.

When I set up my recurves 25 years ago I selected the shaft size from the arrow chart (the charts were much better back then) and tuned the bow/arrow combination until they were smooth, had tight groups and the bow was very quiet. Another sign that everything is right is that the set-up is very forgiving of cold fingers. I never weighed my arrows until 6-7 years ago after reading an article that stated that arrows needed to be at least 10gpp. I was almost shocked to see that my arrows are only 7.5-8.0 gpp at my draw length, for my two bows. That got me into the technical side of archery. My heart will always see archery as an art.

I’ve always believed that informed choices will make us better archers.

Good shooting,
Chris


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## Bender (Dec 6, 2006)

"I’ve always believed that informed choices will make us better archers"
Now that is something that I believe we should all get behind and no quibbling over the details!


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## katman (Jun 5, 2006)

Chris, With your experience how wide is the maximum efficiency range? I assume the exact gpp will vary with different setups but is the range 1gpp, 2gpp, 5gpp?


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## LBR (Jan 1, 2004)

> KE determines penetration.........


Not according to what I've read, and not according to the people I've talked to that have hunted/shot/killed huge animals with bow and arrows.

KE is misleading if you want to use it as a penetration guide in archery. For instance, if you are pulling 80# on a compound and shooting a 400 grain arrow, you will get some really big numbers forKE. Say you are getting 320 fps with the 400 grain arrow--that gives you 91 ft lbs of energy. Take a longbow pulling 80#, with an arrow that weighs 1,000 grains, the KE number won't be anywhere near as impressive--say you are getting 160 fps with that set-up. You get only 57 lbs of energy with that. 

Now talk to some guides and hunters that deal with really tough animals--cape buffalo, Asiatic water buffalo, etc. and see which of these two set-ups they would reccomend--based on EXPERIENCE.

I already have, and have heard lots of horror stories about super-fast, very light arrows. I've heard lots of success stories with slow, heavy arrows with a lot less KE. I've done quite a bit of research on this because I had planned a trip to Australia for water buffalo--that one fell through due to an injury, but I hope to try again one day.

From what I can gather, momentum is a much more accurate and reliable indicator of penetration. Simple version (simple is best for me), when you compare the two examples using momentum you get 128 vs 160, with the longbow set-up having the greater momentum. Using KE, you would think the compound should get near double the penetration of the longbow, when the longbow with a heavy arrow will out-penetrate the compound and lighter arrow.

Dr. Ashby's report goes into great detail if you want the numbers, and both he and many hunters and guides who have "been there, done that" can give real life experiences as well. It gets pretty deep--I can't get into the formulas without confusing myself--but the numbers don't really matter to me when I know hunters that have proven in real life what the numbers show on paper.

With the original question, I stick to my first answer--there's too many variables for a "one size fits all" answer. Even using momentum, you will have to do some experimenting with your individual set-up to find what works the absolute best.

Chad


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## Jack NZ (Apr 7, 2006)

How do you measure gpp ?


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## WHD 32519 (Oct 17, 2008)

Katman,

Good question, I don’t know, my bows will do at least 1.5gpp but I’ve never really played with it. I’ve shot 650 grain arrows out of 50lb bows that did fine and the same arrows out of 60 lb bows that did lousy. I think that the total energy of the bow( weight and speed) has a lot to do with it. What you gain on one end you may loose on the other.

Chad, 

Hunting scenarios have way too many variables to use for penetration comparison. However, I do agree in principle with that point. I agree with almost everything you said. I think that in the real world of hunting penetration is way over played, I’ve never had an animal stop my arrow so I look more at take-down power, big broadheads and the power to drive them home.

Two points:

Once an arrow is in flight it doesn’t matter what kind of bow launched it. I’m certainly not going to challenge the laws of physics.

As for the example of a compound vs. longbow, would you settle for a compound vs. recurve?

I have a 2003 Martin Septer III, #74 with Fury X cams, which have a 65% let off. 525 grain arrow, Easton 2315 XX78 vs. the faster #80 recurve shooting an Easton 2317 at 650 grains. Real life, first hand, me, experience. Shooting into the same Morrell target. No contest. The compound arrows penetrate about 50% more which is equal to the difference in the KE. 525 [email protected] vs. [email protected] I used to think that KE was the wrong formula also, and I still scratch my head and wonder but the energy to stop the arrow is by definition KE. All we really have to do is shoot arrows into a target to prove or disprove almost any point we aren’t sure of. That’s what I’ve done.

You’re absolutely right….there is no way one size fits all. Everyone needs to find what works best for their individual set-up.

Good shooting,
Chris

PS: Jack NZ, Total arrow weight in grains divided by draw weight at your draw length. Grains per pound


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## Jack NZ (Apr 7, 2006)

Thanks,,,for the thread as well.


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## LBR (Jan 1, 2004)

I agree that there's gobs of variables with hunting, but Dr. Ashby has the numbers PLUS hunting shots PLUS shots on dead animals.

I personally haven't had any penetration problems, and don't worry about it with anything in North America with the set-up I shoot now. I did do a lot of research when I was planning to leave for Australia, and regardless what the numbers say, or whether you feel KE or Momentum is the best way to figure it out, the guys that kill these critters say the same thing. Talk to Rick McGowan (Rick is both a buffalo hunter and guide), Cory Mattson, Dr. Don Thomas, Dr. Ed Ashby, Monty Browning, etc. I've talked with several of these, and also talked with the late great Aussie guide Billy "Boomslang Bill" Baker. If I get to go, I plan to contact his son, who is still guiding as I understand it. I also talked with an African guide--Kruger was his partial name (or maybe his internet moniker), I forget the rest--he said the same thing concerning Cape buffalo. Folks I've talked to that have taken both say there's no difference in what it takes to kill either one.

The target thing puzzled me when I first started researching this stuff, until someone explained it. I know that in some cases a faster, lighter arrow will out-penetrate a slower, heavier one--in some target mediums. What I learned is targets are a certain type of medium--period. With animals, particularly buffallo, you have mud, hair, hide, flesh, bone, and organs, with water/blood acting as a lubricant. That makes a difference. You don't get accurate penetration tests concerning animals by shooting into foam.

Also consider this--have you ever shot a bucket or jug of sand with a rifle bullet and an arrow? That's an old demonstration Mr. Dan Quillian used to do (back when you could take a rifle to a county fair) to promote the lethality of a bow and arrow when fighting to get a legitamate archery season established in GA. 

I'm pretty sure, even without doing the math, your everyday run-of-the-mill 30-30 is going to have considerably more KE than any arrow you can shoot--but which one will penetrate the jug of sand? It's not just the amount of KE, it's how that KE is dispersed, how much can be maintained, and for how long. Nobody in their right mind would consider tackling a Cape or Asiatic buffalo with a 30-30 or a 30.06, but they have been taken cleanly with traditional bows producing far less energy.

Anyhow, I'm not smart enough to even try to argue the math/physics--but I am smart enough to have talked to a bunch of folks with hands-on experience.:wink: 

Chad


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## WHD 32519 (Oct 17, 2008)

Chad,

I sure am glad you’re not mad at me for disagreeing about the compound/ recurve penetration. 

Bucket of sand, high speed impacts cause a shockwave, all of the bullets’ energy went into it, do it with a bucket of water and you’ll really see the shockwave. Energy doesn’t vanish into thin air.

Most of the problems with high speed compounds are just like mine. Because the set-up is basically an overdraw and there isn’t enough room to use a bigger broadhead so I have to use small 100 grain broadheads which will blow through an animal without much damage. If I were to go hunting for Cape buffalo you bet it would be with the recurves and 150 and 170 grain broadheads, I don’t care about penetration as long as it’s enough. Besides I can get three more arrows off in the time it would take to reload and shoot that compound. Fred Bear usually had someone standing behind him with a big gun.

Comparing hunting and target shooting is kind of like comparing apples and oranges. I still think that using a consistent resistant target is a good way to check the energy efficiency of shooting different weight arrows out of a given bow. For people without chronographs it may be the only way.

Good shooting,
Chris


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## LBR (Jan 1, 2004)

> I sure am glad you’re not mad at me for disagreeing about the compound/ recurve penetration.


Lol--I'd never get mad over an intelligent and honest conversation or debate. Yours is obviously both, we're just looking at it from different angles.



> Bucket of sand, high speed impacts cause a shockwave, all of the bullets’ energy went into it, do it with a bucket of water and you’ll really see the shockwave. Energy doesn’t vanish into thin air.


I agree--my point was with different target mediums, you can get different results. Sorry--I should have clarified.



> Comparing hunting and target shooting is kind of like comparing apples and oranges.


I get your point (I think), and agree.



> I still think that using a consistent resistant target is a good way to check the energy efficiency of shooting different weight arrows out of a given bow.


It should be, or it's at least one way to measure. The "catch" is, as usual, in the variables. Not just arrow weight, but the point type, FOC, tuning, shaft material, shaft diameter, etc. etc. etc. Neither KE or momentum takes those into account.



> ...I don’t care about penetration as long as it’s enough.


This is a point where I disagree with Dr. Ashby and have bumped heads (mildly) with O.L. Adcock. I feel the same as you--I don't care how fast my arrow passes through the animal, or how far it sticks into the dirt/tree/whatever after it passes through. There are things I could do increase performance with my set-up (to the point where, according to Dr. Ashby, I could hunt water buffalo with it)--but I'm not going to, because I like it as-is and it will shoot through anything I care to shoot at with it.

O.L. loves to push the envelope with performance. Dr. Ashby doesn't seem to think there's a such thing as overkill. I respect them both, and enjoy talking with both, but don't agree on those points.

Anyhow, I appreciate the conversation. I'll keep looking into penetration and how to improve it, because I still hope to make it to Oz and chase water buffalo before I'm too old and stiff to pull back an 80+ lb longbow.

Chad


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## Sanford (Jan 26, 2009)

This has been a very informative thread. Could someone explain the math? This stuff can be confusing to a newbie. I have been shooting wood - 45 spine from a #[email protected]" Martin Stick. My draw is 27", pulling #45.

Recently I decided to switch to a narrower carbon arrow due to smaller shelf on the Stick. A recommend target arrow, per my local range, was a Beman ICS Hunter 500.

After reading through this thread, I find some information about my new carbon arrows that I do not understand. The rating, per the arrow identification sticker, states 7.3gpi. In this thread, ya'll talk about gpp. Are the measures (gpi & gpp) related, and if so, how?

Thanks in advance.

Edit to add: Heck, I forgot the second part to my question. Are these arrows too light at 7.3 gpi?


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## Bender (Dec 6, 2006)

gpi=grains per inch gpp=grains per pound (of draw weight) 
Toatl mass including point must be accounted for to calculate gpp.


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## Sanford (Jan 26, 2009)

Bender said:


> gpi=grains per inch gpp=grains per pound (of draw weight)
> Toatl mass including point must be accounted for to calculate gpp.


Thanks Bender. I'm lost on the math. Do I calculate the total weight of the arrow (including point) and then divide by the draw weight in order to get gpp? That would make intuitive sense but makes for a light 7.1 for my arrows, unless too light is pretty subjective.


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## LBR (Jan 1, 2004)

> Do I calculate the total weight of the arrow (including point) and then divide by the draw weight in order to get gpp?


Yes. If your arrow is 400 grains (total--point, nock, feathers, etc.) and you are pulling 50# at your draw, you have 8 gpp.



> That would make intuitive sense but makes for a light 7.1 for my arrows, unless too light is pretty subjective.


Depends on the bow. Most bowyers/companies want you to shoot a minimum of 8 gpp to stay within the warranty specs.

The gpi just gives you an idea of what the "naked" shaft will weigh at a certain length. For instance, if your shafts are 7.3 gpi, and you use a 30" shaft, you know the shaft alone will weigh 219 grains. Then you allow for the nock, insert, feathers, and point to get an idea of what your finished arrow will weigh.

Chad


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## Sanford (Jan 26, 2009)

LBR said:


> Yes. If your arrow is 400 grains (total--point, nock, feathers, etc.) and you are pulling 50# at your draw, you have 8 gpp.
> 
> 
> 
> ...


Great! Got it now. Thanks.


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## Jack NZ (Apr 7, 2006)

Sandford,
A good friend of mine got into bow hunting last year and the arrows we ended up choosing for him are the Beman ICS 500.
he's shooting 40lb and we put 100g brass inserts into full length shafts with 100g broadheads.
This is just the combo that got it shooting straight.
As to weather the arrow is too light,,he shot his first big game animal with it a couple of months ago, and got a total pass through on a 100lb Boar.
How light for the bow,,,Dunno,hasn't blown up yet:wink: 
My own target wheight arrows work out at 6.72 PP.
Hunting,9.6 and 10.4
I know 6.72 sounds very light and I have been warned "several times" it will void my warranty and may also damage the bow.
In reply to that,all I can say is that the bow is set up with shockblockers on the limbs,a short Reflex shock absorbing stabilizer and it's only slightly louder to shoot than it is with my 520g arrows.
As far as the warranty is concerned,I think I blew that the day I bolted Samick limbs to a Hoyt riser


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## BLACK WOLF (Aug 26, 2005)

Let's run it through the numbers.

After a little more research...I found the general rule is for every 6 grains of arrow weight you will increase or decrease the arrow's speed by 1 fps.

Let's start with some typical numbers some trad shooter might see. 

One specific 55lbs. bow and archer are getting 185 fps. with a 550 g. arrow. 

GPP = 10 
KE = 41.79
MO = 14.54

Now let's compare numbers with a 650 g. arrow. Based on increasing the arrow weight by 100 g. out of the same bow...the arrow's speed will be decreased by about 16.6 fps.

So now arrow speed = @168fps for 650 g. arrow

GPP = 11.8 
KE = 41.7
Mo = 15.6

Now let's compare 750 g. at 152 fps

GPP = 13.6 
KE = 37.46
MO = 16.29

850 g. at 135 fps

GPP = 15.4 
KE = 34.39
MO = 16.39

950 g. at 119

GPP = 17.1 
KE = 30.37
MO = 16.15

450 g. at 202 fps.

GPP = 8.1
KE = 39.66
MO = 12.99

Based on this particular bow and archer if he believes KE determines an arrow's penetrating potential than his best choice would be the original arrow at 10 gpp at 550 g. going 185 fps.

If he believed MO determines potential penetration than he would choose 15.4 gpp at 850 g going 135 fps.

The KE numbers are approximations taken from a chart.

There's another factor that some believe might be the true measure of an arrow's penetrating potential called Kinetic Pulse...but that's a different discussion 

Ray


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## BLACK WOLF (Aug 26, 2005)

Now that you guys can see the numbers...I'm curious to know what your thoughts are.

Ray


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## Sanford (Jan 26, 2009)

BLACK WOLF said:


> Now that you guys can see the numbers...I'm curious to know what your thoughts are.
> 
> Ray


BW, thanks for supplying the numbers. I am starting to see light now. The relationship of arrow weight, spine, and draw weight make a lot more sense to me now. Shooting my carbons and comparing against my woods (which are much heavier, how much I have to determine by scale) I can attest to deeper penetration with the woods. They go much deeper into the range target for the same distance and pull.

I can also start to see that mere compensation for weight at the point is not that straightforward - at some point the weight will overbear on the spine of the arrow. Trial testing seems the best way to navigate this stuff, but your chart gives me some good insight on where things can break down at extremes.

Thanks again.


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## BLACK WOLF (Aug 26, 2005)

Yea...it's quite hard to eliminate all the variables in an actual test.

To make a test more conclusive regarding just KE or MO you would need to test arrows of at least the same tuning, diameter, material, FOC and fletching.

It would definitely take alot of work!

But those numbers I've posted above are indicators of an arrow's penetrating potential if all other things were equal.

It definitely should give a bowhunter a better understanding of maximizing arrow penetration based on 1 particular bow and arrow combination.

Once they've done that...they can further increase their arrow's penetrating potential by using arrows with a smaller diameter, increasing FOC, using broadheads with less drag, picking an arrow material that recovers quicker upon impact, etc. etc.

Ray


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## WHD 32519 (Oct 17, 2008)

Stanford,

I use 7.5-8.0 gpp arrows on my two #80 recurves, which I’ve been shooting for over 25 years. After shooting well over a 100,000 arrows there is no damage to the bows and they still shoot just like new. I didn’t know what my arrows weighted until 6-7 years ago when I weighted them for the first time ever. The arrows shoot smooth, group well and the bow is quiet. That was the standard back then.

Ray,

In trading speed for weight have you ever noticed a point where the performance of the bow just falls beyond the normal trade-off? I don’t shoot 10+gpp very often and only with other peoples’ bows, some of the bows have done okay and other bows the performance was not something I would consider hunting with. I know about shooting arrows that are too light, noise and vibration are usually a sure give away. How would someone know that they are shooting an arrow that is too heavy?

Good shooting,
Chris


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## Sanford (Jan 26, 2009)

WHD 32519 said:


> Stanford,
> 
> I use 7.5-8.0 gpp arrows on my two #80 recurves, which I’ve been shooting for over 25 years. After shooting well over a 100,000 arrows there is no damage to the bows and they still shoot just like new. I didn’t know what my arrows weighted until 6-7 years ago when I weighted them for the first time ever. The arrows shoot smooth, group well and the bow is quiet. That was the standard back then.
> 
> ...


Thanks. I haven't made it to the scale yet, but mine should be right at your 7.5 gpp on final weight or more [(27" x 7.3gpi + 145 g point)/#45 = 7.6gpp]. As suggested, throwing in the nock, feathers, and insert, and it would appear I am not too light, considering they continue to shoot acceptably. This, I will find out after a couple more shoots - I will be paying better attention to how the arrows fly and how the bow reacts.


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## BLACK WOLF (Aug 26, 2005)

WHD 32519 said:


> In trading speed for weight have you ever noticed a point where the performance of the bow just falls beyond the normal trade-off?


I personally haven't because I really haven't paid a whole lot of attention to it. I basically just shot arrows that were spined for my draw weight and draw length and tuned them until I was getting perfect arrow flight.

It wasn't until a couple of years ago did I start purposely trying to improve my penetration potential.

I had shot 2 elk with Easton's 2419 aluminum arrows that weighed around 610 g. with a 2 blade Ribtek one year and a Wensel 3 blade Woodsman the next and was not pleased with the penetration...so the following year I tried some heavier Grizzly Stiks with a Shkote 2 blade broadhead weighing about 720g. thinking the heavier shaft might make the difference.

I was surprised and disappointed at the penetration that both I and one of my hunting buddies got with our new Heavier arrow set-ups that year and decided to try some new Easton Axis arrows remembering how much further skinny carbons always penetrated more into the target mediums.

Well...I finally got the penetration I was looking for and I believe it was primarily do to the shaft's smaller diameter...even though increased FOC and a slightly better broadhead was used.

I believe I could get complete pass throughs with the previous heavier arrows if they were just smaller in diameter and used STOS broadheads.

Even though the previous broadheads were of good design and were sharp I really think the STOS and smaller diameter shaft made just enough difference to blow through my last elk like a hot knife through butter...which is what I was looking for.



WHD 32519 said:


> How would someone know that they are shooting an arrow that is too heavy?


I would say...an archer can tell by one or 2 ways.

One...run the tests I just did comparing the numbers. Depending on what you personally believe determines an arrow's penetration...be it KE or MO...find out at what point do you start loosing energy and when you find that...that's when the arrow's too heavy.

The other would be a decrease in accuracy due from using to heavy and to slow of an arrow to the point your accuracy begins to be less consistant.

Ray


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## WHD 32519 (Oct 17, 2008)

Ray,

I shoot #80 bows so penetration was never an issue for me. I almost lost two deer because of using small broadsheads, little or no blood trail in a high density deer area. So I went for using bigger broadheads. Like you I selected the right spine and tuned everything until the arrows seem to glide out of the bow. The bows have no shock or noise and are very forgiving which I was taught was a sure sign that I’d gotten it right. Shot them this way for nearly 20 years.

Then I read an article telling me my arrows are too light. I’ve often wondered could I get more out of the bows, but I’m not sure what “more” I’d be trying to get.

I think I’m like many others who can’t find a formula to explain everything that I experience. One thing I am sure of is that heavy arrows don’t deflect as easily as lighter arrows, which has got to be a factor in hunting and is probably what Chad is talking about.

I think we should write our own rules as they apply to archery.

Archery was much simpler when I saw it as an art.

Good shooting,
Chris


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## BLACK WOLF (Aug 26, 2005)

Chris,

I agree. Most of our choices are a balance between give and take until we find the right combination that meets our goals.

I'm a competitive target archer also so I like a faster arrow. I like to compete with the same equipment I hunt with so I'm willing to give up a little bit more MO for a faster lighter arrow.

I hunt and compete with 70lbs. bows and I knew complete pass throughs on elk were possible but I just wasn't achieving it. Whitetail were no problem.

We don't need formulas to explain how everything works...but for some of us more analytical types...those formulas can help explain it.

Personally...I also believe we should write our own rules...but it's good to have resources with info that can help us make more informed decisions.

Ray


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## WHD 32519 (Oct 17, 2008)

Ray, 

I find it interesting that you experienced first hand that heavier arrows alone do not make for better penetration. That is consistant with the theory about once you're getting all the energy out of the bow you've got to find it somewhere else.

Good shooting,
Chris

PS: Can you tell I'm not working today? Regular days off.


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## BLACK WOLF (Aug 26, 2005)

WHD 32519 said:


> I find it interesting that you experienced first hand that heavier arrows alone do not make for better penetration.


Chris,

Ya nailed it right there  

There seems to be a few bowhunters that believe that by just going heavier they will automatically increase their arrow's penetrating potential without taking into account the other factors that can have a greater effect on penetration than just arrow weight alone.

The factor that I believe has the greatest effect in how well an arrow will penetrate...is tuning...which is one of the reasons I'm so anal about tuning 

There can be so much energy wasted when an improperly tuned arrow hits a deer...that it can dramatically effect it's penetration no matter how heavy the arrow is...which is one of the resons why we will hear stories of lighter arrows getting pass throughs when some heavy arrows only get marginal penetration.

Ray


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