# GPP for deer hunting?



## Stub (Aug 13, 2013)

Hello guys,

Wondering what GPP you guys will be shooting this Fall's deer season? I talked to a few guys already, via emails and PMs. Still a little confused what the "best" GPP is, or if there is a "best". Right now with my set-up, I'm looking at 12.25 GPP with 175g up front. I talked to guys shooting 9-10 GPP with 125g tip and guys shooting 13-14 GPP with 175g+ tip/weights. So really just curious if there is a "best" as far as hunting deer is concerned. Is it better for trad bows to go with slow, heavy arrows or fast, light arrows?

I'm asking because currently I practice with a 175 point (588g total arrow wt.). Just so I can get the gap/trajectory down and know my distances. If its better to go somewhere around 10GPP, then I might fork over some money and get some lighter carbons. 

Anyways just wanted to see what you more experienced bow hunters are using. Or if this is your first year like myself. Would also like to know what you are using.

Thanks!


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## ghostgoblin22 (May 3, 2013)

tagged for later, interested on everyone set ups as well, i have a 50# samick sage and trying to find the correct arrow and broadhead combo for it

would love to know what the pro's are using!


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## MGF (Oct 27, 2012)

I don't know that there is a "best". It just depends what you're after. I'm shooting about 12 but I tuned with a long arrow to give me small gaps and a short "point on". That's not going to give me as flat of a trajectory as I could get with a lighter arrow but it'll work for the way I hunt.


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## ghostgoblin22 (May 3, 2013)

heres my set up so far

Gold Tip Warrior extreme arrows-400 spine-8.2 G.P.I- 31'' arrow length-160 grain zwickey eskimo 2 blade broadhead

the total weight in my arrow is roughly 435 out of my 52# samick sage

this set up is for deer of course

does this set up sound about right?


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## J. Wesbrock (Dec 17, 2003)

None of the above.


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## SPTiger (Dec 18, 2007)

ghostgoblin22 said:


> tagged for later, interested on everyone set ups as well, i have a 50# samick sage and trying to find the correct arrow and broadhead combo for it
> 
> would love to know what the pro's are using!


Not a pro by a long shot, but I'm shooting 30.5" Gold Tip 5575 Traditional shafts with my 50# Samick Sage w/100 grain heads. I'm only at 8.5 GPP, but since it shoots so well I don't want to change anything. The broadheads that I've shot with that bow are 100 grain Zwickey 2-blade broadheads. Have not hunted with this setup but I plan on it this fall.


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## ghostgoblin22 (May 3, 2013)

SPTiger said:


> Not a pro by a long shot, but I'm shooting 30.5" Gold Tip 5575 Traditional shafts with my 50# Samick Sage w/100 grain heads. I'm only at 8.5 GPP, but since it shoots so well I don't want to change anything. The broadheads that I've shot with that bow are 100 grain Zwickey 2-blade broadheads. Have not hunted with this setup but I plan on it this fall.


Do you know the total
Weight of your arrow?


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## fieldnfeathers (Nov 7, 2013)

8.5 gpp


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## SPTiger (Dec 18, 2007)

ghostgoblin22 said:


> Do you know the total
> Weight of your arrow?


It's exactly 425 grains IIRC. I can weigh them again when I get home to be sure.


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## ghostgoblin22 (May 3, 2013)

SPTiger said:


> It's exactly 425 grains IIRC. I can weigh them again when I get home to be sure.


yeah were about the same, mine is 435 but i have a 160 grain broadhead for more FOC....


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## JParanee (Oct 13, 2009)

I'm averaging 9.5 on my setups


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## MoSportsman (Mar 21, 2014)

I am not going to click on the survey till I hear the definitive definition of GPP?
I am shooting GT trad 35/55 500 8.6 GPI 30.5 inches total weight of about 495, 200 gr heads 20% FOC. 48# @ 28"
If GPP means what I think it does total weight divided by arrow length then that would be 16 GPP
I chronograph this rig before I got a new fast flight string and was averaging around 165 fps I will be interested to see what the fast flight does.
First year with recurve.


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## fieldnfeathers (Nov 7, 2013)

MoSportsman said:


> I am not going to click on the survey till I hear the definitive definition of GPP?
> I am shooting GT trad 35/55 500 8.6 GPI 30.5 inches total weight of about 495, 200 gr heads 20% FOC. 48# @ 28"
> If GPP means what I think it does total weight divided by arrow length then that would be 16 GPP
> I chronograph this rig before I got a new fast flight string and was averaging around 165 fps I will be interested to see what the fast flight does.
> First year with recurve.


GPP is total arrow weight divided by bow draw weight.


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## MoSportsman (Mar 21, 2014)

OK I was confused I would be at 10.3 then.


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## gr4vitas (May 25, 2013)

GPP is pretty irrelevant. 

What's more relevant is your draw weight. We know heavier is better, but only as long as you can accurately estimate your arrow arc, which gets harder the slower the arrow.

So, stack the arrow weight as long as your still happy with the speed. Otherwise more draw weight is the only way to get more KE out of it.

Edit: Obviously there are limits to ether side, but within reason the above.


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## ghostgoblin22 (May 3, 2013)

In liking the skinny carbon with lots of foc up front


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## Stub (Aug 13, 2013)

Thanks guys,

Interesting so far, I figured there would of been more people voting on the heavier side.


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## Jim Casto Jr (Aug 20, 2002)

I've always shot about 9 gpp, and never paid any attention to FOC. Always shoot through everything from deer to bear, pigs, caribou, elk and moose. Lighter is okay for deer too. 

I've always been amazed at folks who say you have to shoot at least a 400 grain arrow out of a 40# bow, then turn around a say 400 grains is too light for a 60# bow. :^)


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## Bill 2311 (Jun 24, 2005)

In this forum, you will find more light weight arrow shooters than say on Tradtalk or Tradgang. I can only image how light some guys will go, but I suspect a bunch will be at 8 grains per pound. My personal limit is 400 grains. It really depends upon the arrow choice. My .400 carbons run 435 grains with a 125 tip. I can also shoot a 2018 with a 125 tip and that runs over 500 grains. The wood shaft can easily run over 700 grains, especially if a maple or ash shaft.


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## MoSportsman (Mar 21, 2014)

I have been running arrows through deer since 1979 and have had very few non recovered deer mostly using 100gr heads and not knowing from Adam what my arrow weighed or much of anything else, just that my broad head arrows hit the same place as my field points. As I decided to try to get a deer with a recurve I recalled a story from a friend from years ago where he shot a deer and got very little penetration and that was when he gave up on the recurve. I wanted to be confident in the equipment and started researching this damn web. Information overload for sure, but after doing the research and the logic in the physics of it all, I like what Ashby has to say and I am going to take it to the level I believe I need. High FOC, heavy total arrow weight, two single bevel blades. It all makes sense to me so I am buying in.

Lightning fast flat shooting arrows have killed a lot of critters in the last 30 years of archery but the speed is designed to make it easier on the average and beginning archer. I feel like the archery industry has not been too concerned with figuring out if that speed was the best thing to do the best job of killing and recovering the game we shoot. But that might not sell as many bows and arrows. Just like the rest of our society easier is better. I don't really mean to be critical of the archery industry I just always follow the money trail and am suspicious of it.


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## fieldnfeathers (Nov 7, 2013)

For me, personally, it has nothing to do with having to obtain the fastest arrows. If it was, I most certainly wouldn't be shooting a recurve. I've killed well over 50 whitetail in my life with archery equipment. For me, a faster arrow speed is about "forgiveness" in range estimation when faced with the adrenaline rush of the hunt. Is it easier? I would say so, I suppose. However, as a hunter first, I owe it to that animal to be the best that I can be at any given time. That just so happens to include a faster arrow.


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## Big Country (Apr 25, 2003)

MoSportsman, regarding the archery industry not being concerned with finding the best arrow weight/speed/FOC for killing game……..there are way too many variables to definitively say that one formula works best. I will agree that speed sells, and since the bow and arrow have already been invented, speed is the easiest way for manufacturers to push new products. 

BTW, I buy into Dr. Ashby`s position on penetration, with a caveat….when hunting whitetail deer, black bear, or other similar sized animals with relatively thin skin, many of us are shooting more than enough draw weight, and arrow weight. The biggest gain in KE and momentum comes from a huge draw length. 

To the original question…….I shoot between 9.5 and 10.5GPP depending on the bow I am using. For critters bigger and tougher than the typical North American game animals, that number goes up. If my draw length was 32" I would shoot less GPP for deer and black bear.


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## BLACK WOLF (Aug 26, 2005)

Big Country said:


> MoSportsman, regarding the archery industry not being concerned with finding the best arrow weight/speed/FOC for killing game……..there are way too many variables to definitively say that one formula works best.


Really...there's NOT one best formula to say what works best. Ya know.....the same thing really applies to form or aiming techniques too :wink:



Big Country said:


> BTW, I buy into Dr. Ashby`s position on penetration, with a caveat….when hunting whitetail deer, black bear, or other similar sized animals with relatively thin skin, many of us are shooting more than enough draw weight, and arrow weight. The biggest gain in KE and momentum comes from a huge draw length.


:thumbs_up

To the OP

I personally use 8g./lbs. and I primarily hunt elk.

I shoot a 70lbs. DAS with Easton Axis 300 arrows 30" long and a Centaur Big Game head.

Ray :shade:


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## Big Country (Apr 25, 2003)

Ray, could you show me just one example where anybody here has stated there is only one best way to shoot a bow? Just one will be great.

Oh, and no liberal spin tactics…...


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## Str8 Shooter (Oct 15, 2005)

I'd vote but there isn't a category under 9 gpp. 

Personally, I prefer a certain arrow speed and trajectory. Depending on the bow it normally falls somewhere in the 6-8 gpp range. For deer I normally shoot 320-340 gr. arrows (total weight). Last season I shot much heavier arrows and didn't really like the trajectory. So, I'll stick with my light arrows and 100 gr. broadheads and shoot with confidence.

Oh, bow weight is between 42-50 pounds. If I hunted something where I needed more energy I'd up the arrow weight and draw weight proportionally to maintain the same trajectory I like.


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## JINKSTER (Mar 19, 2011)

I like 12GPP...seems to have a nice predictable arc for me that carries some umph (in case of encountering a rib) and keeps my bow nice and quiet...check this out...


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## ghostgoblin22 (May 3, 2013)

Can't we all just get along? Lol


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## Stub (Aug 13, 2013)

Thanks for that video Bill.

To be honest I don't understand the physics behind it really. Lighter arrow travels faster, but yet the heavy arrow penetrates further? I tested both 9.5 gpp and 12.25 gpp on hay and I couldn't see a difference in penetration, just different arcs. Would that test yield the same results if your target was farther away?

Sorry for the "noobish" questions, just trying to understand it all


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## Big Country (Apr 25, 2003)

Stub, all else being equal, (outside diameter, exterior finish, etc.) a heavier object will be harder to stop than a lighter object. There is no arguing that point. As it pertains to arrows and hunting though, there are so many variables when running an arrow through an animal, that sometimes we get false results, and we are usually employing "overkill" in the first place. The best suggestion I can make is to keep arrow weight with a recurve/longbow at 400 grains or above, and be sure to use a sturdy and SHARP broadhead out of a well tuned bow. That is not to say that a lighter arrow will not work, because it will, but I have seen ultra light arrows be stopped when a heavier one would make it through.


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## Homey88 (Dec 10, 2013)

I'm going to be shooting 12.1 GOP in the fall. I'm a rookie so hopefully this set up will workout!


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## BLACK WOLF (Aug 26, 2005)

Big Country said:


> Ray, could you show me just one example where anybody here has stated there is only one best way to shoot a bow? Just one will be great.


Allot of it comes down to debate regarding aspects of form. A recent example was in regards to a discussion regarding Dynamic and Static Release. There were a few here claiming a Static/Dead release was basically stupid to teach anyone and how ineffective it was. Maybe you remember it??? If not you can ask Matt or Ben more about it :wink:

The same type of debate is often applied to arrow weight. There are some people who insist a bowhunter needs to be using at 9g./lbs. if not more...but you and I at least agree that that is just not true. Again...the same thing can also apply to form and aiming techniques. There are just soooo many variables based on the archer, the animal, the bow, etc. etc. that there really is no one best answer for everyone.

Ray :shade:


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## MacIndust (Feb 7, 2012)

I shot both my deer last year at about 8.5p and the results were good. I find my bows seem happier around 9-10, though.


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## grantmac (May 31, 2007)

I generally gap shoot best with full length arrows going ~180fps. So for most of my bows I want an arrow around 400gr with at least 150gr in the front.

-Grant


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## ranchoarcher (Sep 26, 2013)

7.7 on the last major hunt. It will depend on your bow, your ability, and very much on expected target distances. If it's up close around 20 yards anything will probably be ok. Beyond that and you're looking at having to gauge distances and calculate trajectory. I'd get some arrow tips of various weights and give it a shot at different yardages to see if you can get comfortable with it or not.


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## Roger Savor Sr (Feb 16, 2014)

I shoot between 7-8gpp off 45#-50# bows with no penetration issues whatsoever. It's also noteworthy that my draw length is only 27 1/2".........Oh, and I've even done it with modular broadheads such as the Muzzy and Thunderhead. I've field dressed and weighed PA bucks over 220#, but apparently they are much, much larger elsewhere in this country. LOL


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## Matt_Potter (Apr 13, 2010)

Most of my hunting is done at 7-9 GPP. Get your arrows bare shafting well screw in a sharp broad head and call it good. 

Where you hit an animal is much more important than what you hit it with.


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## FORESTGUMP (May 14, 2008)

Stub, your arrows are just right. Why, because they're the ones you already have and are comfortable with. As you can see the subject of weight runs from super light to super heavy and anywhere in between.
You can look at the Ashby reports for a good read concerning the heavy end of the argument and on youtube for Ken Busalacchi videos for the light end. Both have had good results with each although they are hunting different game.
For deer hunting, happy medium is the place to be and your arrows are there. Maybe a little heavy for my tastes but, no matter. I did notice something in Kens video that I have noticed before in my own meanderings with different arrows. The heavy always makes a more pronounced 'whump' at impact with the target than the lighter ones. May not mean a thing, just something I have noticed over the years. 
Personally, I like about 500gr total give or take 50 and somewhere above 15% foc. Whatever tunes the arrow.


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## Stub (Aug 13, 2013)

Thanks guys for the info. Helps me a lot reading through this thread. I'm starting to get a understanding now. 

I should of added more options in my poll. More lower gpp options. So I apologize for that. I just assumed heavy was the norm when deer hunting. Learned something new. Been doing some thinking, I do like the idea of having a flatter trajectory. So I been looking into some lighter carbon shafts. Wont be anytime soon, but maybe for my next set of shafts I can consider the weight more closely.

Again, thanks guys - Appreciate it!


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## FORESTGUMP (May 14, 2008)

Just for the heck of it, I went to the calculator and used a gold tip traditional 3555 which is available pretty cheap if you buy the blems. I don't remember your drawlength but I used 28' and a 30" shaft with 150gr point.
The result;
Total 448gr.
gpp 9.9
foc 15.9
Exactly what I would have recommended to you. In fact my entries were just a guess but worked out.


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## Stub (Aug 13, 2013)

FORESTGUMP said:


> Just for the heck of it, I went to the calculator and used a gold tip traditional 3555 which is available pretty cheap if you buy the blems. I don't remember your drawlength but I used 28' and a 30" shaft with 150gr point.
> The result;
> Total 448gr.
> gpp 9.9
> ...


Thanks Forest,

This is what I have book marked: http://www.lancasterarchery.com/gold-tip-traditional-hunter-arrow-shaft.html -Hope that's right
I have a 27.5 draw on average. I would like to use a 175g tip however. Already have the 175g points. Then I could also use a big Simmons. 

I'm a little confused on the Gold Tip spine. I'm used to aluminum numbers. 3555 is what I need for a 48# draw weight?


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## FORESTGUMP (May 14, 2008)

Stub said:


> Thanks Forest,
> 
> This is what I have book marked: http://www.lancasterarchery.com/gold-tip-traditional-hunter-arrow-shaft.html -Hope that's right
> I have a 27.5 draw on average. I would like to use a 175g tip however. Already have the 175g points. Then I could also use a big Simmons.
> ...



Don't lock in on my numbers because it was just a quick guess and I had to do some substituting because your bow is not listed so I winged it as best I could. Kegan will be the best source for that information. I'm not even sure the bow is cut to center but, that's what I entered. 
It's very possible that you might need a 5575 for a 175gr point and I understand those bows are a bit on the higher performance side. Personally, I don't care what the point weight is as long as it results in the numbers I posted earlier and a tuned arrow.


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## zu! (Feb 19, 2014)

Forest, do you find that the lighter arrows to be louder off the bow? That's what it seemed like to me. 

I just picked up a half doz goldtip 1535s to try with my 40lb bow. I'm topping them (for now) with the same field tips I'm using on my woodies, 125gr. Without cutting (30") them, they fly like darts to the target and both bare and fletched hit where they're pointed. 

The flight even LOOKS faster than my woodies! But they are definitely louder. I use my iPhone and a decibel meter...they're at least 5 dB louder, lol! 😃


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## longbowguy (Nov 14, 2004)

Whitetail and mule deer are not very big or tough so I would likely hunt with whatever arrows I had been shooting well for other purposes. Dr. Ashby's fine studies were about performance on very large African and Asian game. I have some heavy arrows built along the lines of his recommendations in case I win the lottery and can afford to go hunt something big and bitey. But for deer most any good setup and any broadhead will do fine. Having a longish draw my setups generally are fairly heavy for draw weight to get the trajectory my eye is used to. - lbg


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## FORESTGUMP (May 14, 2008)

zu! said:


> Forest, do you find that the lighter arrows to be louder off the bow? That's what it seemed like to me.
> 
> I just picked up a half doz goldtip 1535s to try with my 40lb bow. I'm topping them (for now) with the same field tips I'm using on my woodies, 125gr. Without cutting (30") them, they fly like darts to the target and both bare and fletched hit where they're pointed.
> 
> The flight even LOOKS faster than my woodies! But they are definitely louder. I use my iPhone and a decibel meter...they're at least 5 dB louder, lol! &#55357;&#56835;


Definitely, which contributes to my love hate relationship with carbon shafts. To me, it's a good reason to use a stiffer shaft and heavier point weight. A balancing act for sure.


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## rattus58 (Jul 9, 2007)

Stub said:


> Hello guys,
> 
> Wondering what GPP you guys will be shooting this Fall's deer season? I talked to a few guys already, via emails and PMs. Still a little confused what the "best" GPP is, or if there is a "best". Right now with my set-up, I'm looking at 12.25 GPP with 175g up front. I talked to guys shooting 9-10 GPP with 125g tip and guys shooting 13-14 GPP with 175g+ tip/weights. So really just curious if there is a "best" as far as hunting deer is concerned. Is it better for trad bows to go with slow, heavy arrows or fast, light arrows?
> 
> ...


there aint no "best" GPP... but one that gives you penetration and comfortable trajectory. The lower the GPP, then adjusted for spine, you should consider a forward CG, in my opinion, to aid in penetration as your draw weight drops. Fred Bear and a host of other old timers who wrote about this stuff, liked a minimum of 8 to 10 grains per pound of draw weight. The higher the draw weight, the less forward CG matters in penetration, in my opinion, and proper tuning is the focus. I'd not be using less than 8 GPP for hunting though if you don't need to for speed/trajectory issues where forward CG (FOC) comes into play again.


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## Roger Savor Sr (Feb 16, 2014)

I just don't think some can fathom how very little it takes from a tuned setup to fully penetrate deer. My 13yr old son took his first bow killed deer this past fall. The draw length on his little compound was set at 23" and a peak weight of 38#. The arrow is 330gr, travelling at 175fps. A 100gr Stinger Buzzcut 2 blade was his broadhead choice. The arrow entered on the back half of the near side shoulder muscle and exited just behind the off shoulder muscle. We found that arrow about 10' past the spot the deer was standing at the shot. Dead deer inside 20 yards.


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## Jim Casto Jr (Aug 20, 2002)

Roger Savor Sr said:


> I just don't think some can fathom how very little it takes from a tuned setup to fully penetrate deer. My 13yr old son took his first bow killed deer this past fall. The draw length on his little compound was set at 23" and a peak weight of 38#. The arrow is 330gr, travelling at 175fps. A 100gr Stinger Buzzcut 2 blade was his broadhead choice. The arrow entered on the back half of the near side shoulder muscle and exited just behind the off shoulder muscle. We found that arrow about 10' past the spot the deer was standing at the shot. Dead deer inside 20 yards.


EXACLTY! Problem is some of the folks offering their advice here, don't even hunt, and some have read some unscientific testing and decided what applies to Cape Buffalo also applies to deer, pronghorns, and bear--their lack of experience notwithstanding, of course.


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## Matt_Potter (Apr 13, 2010)

Jim Casto Jr said:


> EXACLTY! Problem is some of the folks offering their advice here, don't even hunt, and some have read some unscientific testing and decided what applies to Cape Buffalo also applies to deer, pronghorns, and bear--their lack of experience notwithstanding, of course.


Noticed that did you - LOL


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## deadquiet (Jan 25, 2005)

I'm at 11 and really like it but I'm probably still going to add some more point weight.


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## rattus58 (Jul 9, 2007)

Jim Casto Jr said:


> EXACLTY! Problem is some of the folks offering their advice here, don't even hunt, and some have read some unscientific testing and decided what applies to Cape Buffalo also applies to deer, pronghorns, and bear--their lack of experience notwithstanding, of course.


Do tell.... what is it that applies to a deer doesn't apply to a cape buffalo?


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## kegan (Aug 28, 2006)

rattus58 said:


> Do tell.... what is it that applies to a deer doesn't apply to a cape buffalo?


I know if you hit one with a KIA it'll die, the other will get mad and kill you. Does that count?


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## rattus58 (Jul 9, 2007)

kegan said:


> I know if you hit one with a KIA it'll die, the other will get mad and kill you. Does that count?


 Well not sure that's quite the same... however a Kia probably isn't the tool of choice for most hunters... :grin:


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## kegan (Aug 28, 2006)

I still think there's something to be learned there:lol:


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## Mo0se (Sep 24, 2002)

N/A for me too.


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## rattus58 (Jul 9, 2007)

kegan said:


> I still think there's something to be learned there:lol:


:laugh: somewhere.... !


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## Tajue17 (Aug 18, 2005)

56# hill style w/ 640gr doug fur arrow, 50# palmer w/570gr arrow, I usually like at least 12+ gpp for hunting but I wouldn't say its all about penetration I like how my bows feel and sound with heavier arrows, and if I hit bone I feel I do more damage but its just opinion and I use grizz or abowyer heads for bone,, all my hits are pass thrus unless I spined something because it dropped.. if I shot more 3D's or competed I'd be alot lighter for sure.... if I had to gripe about one thing it would be with a self bow the hang time on these heavy arrows,,,, sometimes I start falling asleep waiting for the arrow to make contact I think the deer eats for another minute or too also.


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## Boberau (Dec 15, 2009)

Stub said:


> Thanks for that video Bill.
> 
> To be honest I don't understand the physics behind it really. Lighter arrow travels faster, but yet the heavy arrow penetrates further? I tested both 9.5 gpp and 12.25 gpp on hay and I couldn't see a difference in penetration, just different arcs. Would that test yield the same results if your target was farther away?
> 
> Sorry for the "noobish" questions, just trying to understand it all


I've run a number of tests over the years. And, results have been inconclusive. This last week I ran a test between a 390 grain arrow (7.2 gpp) and a 554 grain arrow (10.3 gpp), both tuned to a 54# Brack. My average penetration at 13 yds. was 16% more with the 554 gr. arrow. But, here's the rub - If I look at 2 standard deviations, the heavy arrow was 7.2" to 11.7" penetration. For the light arrow, the average was 8.2" and two standard deviations between 8.1" and 8.3." If Ashby were reporting, he would only report the average (16% more penetration), make an authoritative statement about that, and move on as if this base information is fact. If I were reporting the results, I would say the test doesn't show a significant difference - the results are inconclusive and that to obtain conclusive information, new, better executed tests would be called for to separate the "background noise" from the information we are trying to obtain.

"Background noise" is the problem. But, what is this "noise?" It could be inconsistent bow arm, anchor, release. It could be inconsistent target density, dinged arrow heads versus pointed heads. This would suggest new, better tests on the one hand.

On the other hand, it would suggest that the real world variation is more important than the arrow weight. That would suggest one controls other things such as a sharp broadhead, a well tuned bow, and a well placed arrow (a well placed arrow being the result of good, consistent bow form and practice). It seems those three things are more important than arrow weight. 

By the way, the 554 grain arrow is what I will hunt Elk and Kudu with this year. The 390 grain arrow brought me a nice 200# black bear in 2011, but I don't plan to hunt with it. My fall back will be a 463 grain arrow (8.6 gpp).


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## rattus58 (Jul 9, 2007)

Boberau said:


> I've run a number of tests over the years. And, results have been inconclusive. This last week I ran a test between a 390 grain arrow (7.2 gpp) and a 554 grain arrow (10.3 gpp), both tuned to a 54# Brack. My average penetration at 13 yds. was 16% more with the 554 gr. arrow. But, here's the rub - If I look at 2 standard deviations, the heavy arrow was 7.2" to 11.7" penetration. For the light arrow, the average was 8.2" and two standard deviations between 8.1" and 8.3." If Ashby were reporting, he would only report the average (16% more penetration), make an authoritative statement about that, and move on as if this base information is fact. If I were reporting the results, I would say the test doesn't show a significant difference - the results are inconclusive and that to obtain conclusive information, new, better executed tests would be called for to separate the "background noise" from the information we are trying to obtain.
> 
> "Background noise" is the problem. But, what is this "noise?" It could be inconsistent bow arm, anchor, release. It could be inconsistent target density, dinged arrow heads versus pointed heads. This would suggest new, better tests on the one hand.
> 
> ...


You were doing so well till you started to tell me what Ashby would do... here you lost ALL CREDIBILITY. Your results are YOUR RESULTS and no one elses.


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## Boberau (Dec 15, 2009)

Frankly, Rattus58, I couldn't care if I have credibility with you. But, I guess you must be someone important, or something ..... right?


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## bwd (Dec 6, 2013)

Since I shoot fairly light weight bows, and have a mental hang up about wanting to be around 500gr. total arrow weight, I'm in the 12gpp range, with generous amount of foc.


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## Hiram (Jul 31, 2013)

I know 10 works,,


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## MGF (Oct 27, 2012)

Boberau said:


> I've run a number of tests over the years. And, results have been inconclusive. This last week I ran a test between a 390 grain arrow (7.2 gpp) and a 554 grain arrow (10.3 gpp), both tuned to a 54# Brack. My average penetration at 13 yds. was 16% more with the 554 gr. arrow. But, here's the rub - If I look at 2 standard deviations, the heavy arrow was 7.2" to 11.7" penetration. For the light arrow, the average was 8.2" and two standard deviations between 8.1" and 8.3." If Ashby were reporting, he would only report the average (16% more penetration), make an authoritative statement about that, and move on as if this base information is fact. If I were reporting the results, I would say the test doesn't show a significant difference - the results are inconclusive and that to obtain conclusive information, new, better executed tests would be called for to separate the "background noise" from the information we are trying to obtain.
> 
> "Background noise" is the problem. But, what is this "noise?" It could be inconsistent bow arm, anchor, release. It could be inconsistent target density, dinged arrow heads versus pointed heads. This would suggest new, better tests on the one hand.
> 
> ...


You're not really giving enough information to assign variability to "background noise". For one thing, a calculation of standard deviation is only valid for a normal distribution. I wouldn't consider shot to shot variations in performance of the archer as "noise", given that the effects can be so significant. 

One technique that is sometimes used where operator (the archer in this case) variability is possible would be to use more than one operator. By comparing the data sets, you can determine what portion of the variability is due to the operator.

Unless it was a typo?...one data set had a standard deviation of more than 2" and the other a standard deviation of 0.1"? That leads me to believe that there was a major flaw in the test someplace.


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## UrbanDeerSlayer (Feb 10, 2012)

GPP Doesn't matter. I have killed deer with as little as 8 gpp. 

What matters is that you have a well tuned arrow, flying straight, with a sharp broadhead, and you hit the deer in the vitals. 

I try to get a good bareshaft tune with field tips first, then broadhead tune. 

So basically what I am saying is that for me, a well tuned arrow trumps any concerns over GPP.


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## Castmaster (May 2, 2013)

In regards to GPP if you are shooting different bows with different draw weights, you can attain a similar arrow trajectory by keeping the GPP the same. To me the only thing that really matters for a hunting set up is total arrow weight. A lighter arrow will be faster but louder, a heavier arrow quieter but slower. I prefer stealth over speed, to me it doesn't matter how fast your bow is if a deer hears the bow shoot off it will react.


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## rattus58 (Jul 9, 2007)

Boberau said:


> Frankly, Rattus58, I couldn't care if I have credibility with you. But, I guess you must be someone important, or something ..... right?


No I'm not important... but I, like many, actually read for content and information with interest in actually learning something, because most posters have a lot to offer in their experiences.... but alas, then you go and pretend you know what Ashby, or me, or bwd, or anyone else would do..... shows that you just make stuff up....


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## zonic (Aug 12, 2013)

Castmaster said:


> To me the only thing that really matters for a hunting set up is total arrow weight. A lighter arrow will be faster but louder, a heavier arrow quieter but slower. I prefer stealth over speed, to me it doesn't matter how fast your bow is if a deer hears the bow shoot off it will react.


I had my Omega perfectly tuned with 500s and 125gr heads. But since reading this thread, I've ordered a few 400s to see if I can't get a heavier head out in front and a little quieter shot. I hope I can get a good tune and that the speed difference w/ carbons will be minimal...


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## Bill 2311 (Jun 24, 2005)

I voted for 9 to 9.99 gpp, but only because the poll does not list less than that.


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