Ideal GPI for Deer Hunting with Lower Weight Compound

[MidMichBow]

Hi everybody,
I just got new strings and all tuned up/sighted in. I'm all set for turkey season. I'm curious your thoughts on ideal gpi for deer hunting; I tend to prefer heavier arrows since that's what I grew up shooting and I'm not pulling a ton of weight (50 lbs on a Bowtech Guardian). I've been using the old Beman's version of what's now the EASTON 6.5MM BOWHUNTER (9.3 gpi). I was trying to buy the Bowhunter's, but they weren't in stock locally. Long story short, I ended up buying the Cabelas/Bass Pro X3 Hunter arrows (same spine, 8.7 gpi - made for them by Gold Tip, I believe). Shooting them side by side, the Cabelas arrows do shoot differently (I can shoot farther with less drop - presumably because of the lower weight). Trying to make a decision for the coming deer season whether to just switch to the Cabelas arrows only or get more of the Eastons. I prefer the Easton brand, but also my wife wouldn't like me spending more $ on hunting... I think mixing is a bad idea per what I already mentioned above. Thanks for your thoughts!

 

[NMSbowhunter]

I have a Mathews HeliM compound set at 44 pounds to use when my rotator cuff is feeling froggy. My other HeliM is set at 60 pounds and I have one arrow setup that I use for both of them. I have one quiver and swap it between both bows as needed. The arrow set up is a 6.5 Easton stock arrow cut 28.25" carbon to carbon with a stock aluminum inset in it. Up front I use a 125 grain Grizzly single bevel broadhead hot glued on a 125 grain steel broadhead adapter. I use a Nocturnal nock on the back. This gives me about 260 grains up front and a total arrow weight of 585 grains. This is a good balance for use on deer from my experience, from both bows. That set up comes out to 20.7 grains per inch.

I shot this buck season before this past one at about 17 yards. He was slight quartering too me and I put the arrow through the scapula on his right side and the arrow exited out behind the shoulder on his left side. He ran all of 25 yards, stood there for a few seconds and tipped over. This was with the 44 pound draw weight bow.

 

[jsh909]

Just go with whichever shoots better. The weight difference isn't enough to matter. Let the bow pick which one for you.

 

[BTaylor]

How far were you shooting to have a noticeable difference? You didnt mention the rest of the arrow build so we cant tell what else might be contributing. Are the diameters the same, fletching the same, front weight the same, nock the same, etc? Also didnt mention arrow length. For a 28" shaft carbon to carbon the difference is only a shade under 17 grains. There are a lot of bowhunters that cant consistently shoot that difference at 20 yards. Not saying you cant by any means, just pointing out, that is not a big enough difference by itself for most folks to see a noticeable difference at normal deer killing range.

For compound arrows I typically decide where I want that arrow to land as far as total arrow weight and range of FOC and build from there starting with front end weight, head and insert. Then add nock and fletching and if you use them, wrap weight. By knowing the exact components you want to use, your shaft selection will mostly be made for you because you are then just selecting for the the right spine with the right gpi to complete the equation for total arrow weight. There are lots of ways to skin the cat, that's just how I prefer to go about it.

 

[MidMichBow]

How far were you shooting to have a noticeable difference? You didnt mention the rest of the arrow build so we cant tell what else might be contributing. Are the diameters the same, fletching the same, front weight the same, nock the same, etc? Also didnt mention arrow length. For a 28" shaft carbon to carbon the difference is only a shade under 17 grains. There are a lot of bowhunters that cant consistently shoot that difference at 20 yards. Not saying you cant by any means, just pointing out, that is not a big enough difference by itself for most folks to see a noticeable difference at normal deer killing range.

For compound arrows I typically decide where I want that arrow to land as far as total arrow weight and range of FOC and build from there starting with front end weight, head and insert. Then add nock and fletching and if you use them, wrap weight. By knowing the exact components you want to use, your shaft selection will mostly be made for you because you are then just selecting for the the right spine with the right gpi to complete the equation for total arrow weight. There are lots of ways to skin the cat, that's just how I prefer to go about it.

Thanks for that. Yes, I neglected to mention some important details. I'm noticing it at 25 yards and out (I won't shoot further than 40 yds in practice and probably only 35 when hunting). Arrow length is 30.5", shooting 100 grain Muzzy's. Same vein type; knocks are slightly different, but I imagine the weight difference there is miniscule. I think the main difference is in the weight of the shaft. All that in mind, I'm probably shooting around 400 grains of weight if I'm calculating right.

Perhaps a better way to phrase the question is: what is your ideal overall weight (grains) for deer hunting? I know it doesn't take a lot to get the job done - I shot deer pulling 25 lbs as a kid with an aluminum arrow. But I'm also no expert with all this stuff so looking for general ideas. Thanks for your help

 

[HawRiverArcher]

I run between 460 (125 tip) and 485 (150 tip) grains TAW out of my compound at 70#. If I turn it down to 60# I just swap out the 125/150 grain tips for a 100 and keep on trucking. I have sight tapes made for each weight that I keep in my bow case.

That comes out to 6.9 GPP for my compound and on my trad bow I run right at 10.2 GPP

 

[BTaylor]

Perhaps a better way to phrase the question is: what is your ideal overall weight (grains) for deer hunting? I know it doesn't take a lot to get the job done - I shot deer pulling 25 lbs as a kid with an aluminum arrow. But I'm also no expert with all this stuff so looking for general ideas. Thanks for your help

Opinions will be all over the board with that questions. Some like light, some heavy and some middle of the road. My preference after trying them all is a set up that's middle of the road to slightly heavy. What I am looking for is the heaviest arrow I can shoot and keep the fps in the 265-285 range. That does a couple of things. It keeps the arrow fast enough to not have huge pin gaps and the other thing is it keeps arrow speed in a range where it is easy to tune any broadhead so switching from fixed to mechanical is not generally a problem at all. Above 285 and esp at 300 or higher, fixed blades can start to get finicky to tune.

My compound arrows are 590 and the fps is 268. With that arrow there is still plenty of mass to drive a big mechanical all the way through most anything I will ever shoot. If you are wanting to stay on the lighter side arrow wise, I would encourage to stay with smaller diameter mechanicals or fixed blades but keep in mind a real fast arrow may be a little difficult to tune.

What is your draw length?

Also there are a couple of arrow calculators online that can be really helpful for getting an arrow set up close. The Stu Miller one is pretty good but there are others.

 

[HawRiverArcher]

Opinions will be all over the board with that questions. Some like light, some heavy and some middle of the road. My preference after trying them all is a set up that's middle of the road to slightly heavy. What I am looking for is the heaviest arrow I can shoot and keep the fps in the 265-285 range. That does a couple of things. It keeps the arrow fast enough to not have huge pin gaps and the other thing is it keeps arrow speed in a range where it is easy to tune any broadhead so switching from fixed to mechanical is not generally a problem at all. Above 285 and esp at 300 or higher, fixed blades can start to get finicky to tune.

My compound arrows are 590 and the fps is 268. With that arrow there is still plenty of mass to drive a big mechanical all the way through most anything I will ever shoot. If you are wanting to stay on the lighter side arrow wise, I would encourage to stay with smaller diameter mechanicals or fixed blades but keep in mind a real fast arrow may be a little difficult to tune.

What is your draw length?

Also there are a couple of arrow calculators online that can be really helpful for getting an arrow set up close. The Stu Miller one is pretty good but there are others.

I am similar. I build an arrow that will stay between 265-275 fps. The end weight isn't really a concern or goal. Whatever it ends up at if I'm still in my velocity target, I don't care. I also know I'll be making shots sub 30 yards (20 or under realistically) in the thick stuff where I hunt. My TAC days are done and my western elk hunts are too for all intents and purposes so I'm not trying to reach out and touch anything long range anymore.

 

[MidMichBow]

Opinions will be all over the board with that questions. Some like light, some heavy and some middle of the road. My preference after trying them all is a set up that's middle of the road to slightly heavy. What I am looking for is the heaviest arrow I can shoot and keep the fps in the 265-285 range. That does a couple of things. It keeps the arrow fast enough to not have huge pin gaps and the other thing is it keeps arrow speed in a range where it is easy to tune any broadhead so switching from fixed to mechanical is not generally a problem at all. Above 285 and esp at 300 or higher, fixed blades can start to get finicky to tune.

My compound arrows are 590 and the fps is 268. With that arrow there is still plenty of mass to drive a big mechanical all the way through most anything I will ever shoot. If you are wanting to stay on the lighter side arrow wise, I would encourage to stay with smaller diameter mechanicals or fixed blades but keep in mind a real fast arrow may be a little difficult to tune.

What is your draw length?

Also there are a couple of arrow calculators online that can be really helpful for getting an arrow set up close. The Stu Miller one is pretty good but there are others.

Thanks for that. I'm right around 30" for my draw length. When I have time, I may check one of the calculators. Honestly, a lot of the nuance is lost on me. I want to learn, but also not sweat the "small stuff." Realistically, I'll be shooting 35 yards and under (most 20 and under) for deer and turkey. If I'm lucky, someday I may get to hunt elk, but that's probably more of a pipe dream. My shooting is consistent, good patterns. So it's more a matter of trying to learn and improve as I make purchasing decisions for the future.

 

[BTaylor]

Thanks for that. I'm right around 30" for my draw length. When I have time, I may check one of the calculators. Honestly, a lot of the nuance is lost on me. I want to learn, but also not sweat the "small stuff." Realistically, I'll be shooting 35 yards and under (most 20 and under) for deer and turkey. If I'm lucky, someday I may get to hunt elk, but that's probably more of a pipe dream. My shooting is consistent, good patterns. So it's more a matter of trying to learn and improve as I make purchasing decisions for the future.

The small stuff would be which camo you wear or climber vs lock on vs saddle, etc. Arrow set up and tune is the exact opposite of the small stuff. Your bow and arrow set up is what does the killing. Accuracy and terminal performance all come from the decisions made around bow tuning and arrow set up. Not saying you should drop everything else and deep dive all things bow tune and arrow set up but would absolutely encourage you to start reading up on it and asking questions to start building that knowledge base.

Maybe the most the important two things to learn imo are spine and dynamic spine. Spine is the actual deflection or bend of the shaft with weight in the center, no fletching, no insert or point, just the shaft. Dynamic spine is how a fully built arrow is going to react when shot, force at the tail end of the arrow. GPI isnt totally irrelevant but it is one of the least important aspects of the whole equation. With dynamic spine, let's say you build an arrow with a standard insert and put a 100 grain head on it. The second arrow you use the same insert but put a 200 grain head on it. The second arrow is going to have a much weaker dynamic spine because it has a lot more weight in the front. You can also, to a lesser extent, impact things by decisions made with what goes on the back of the arrow. Take the same 2 arrows but put 100 grain heads on both. One you fletch with feathers only and a standard nock. The other you add a wrap, 3 vanes and a lighted nock. The second arrow is going to shoot stiffer or have a higher dynamic spine because it has more weight at the rear of the arrow. In those examples you have the exact same shaft with a stated spine and GPI but they will all fly different. Most folks wouldnt put a .308 round in a 30.06 and head to the woods but in some respect that's what a lot of folks do with their bow setup because they dont understand or appreciate the difference every component of an arrow build can make. Poor decisions lead to poor outcomes and the last thing any of us want is to be out there wounding or losing deer due to things we had control over. I 100% do not mean for this to come across like I am busting your chops and hope you take it with the good intentions I had for posting it.

 

[Camelcluch]

GPI doesn’t really matter. Total arrow weight and how the weight is placed and used is what I think you are concerned with. The two arrows have different weight and the distribution of the weight is different. That will give different flight characteristics. Doesn’t mean one is wrong or better. If the bow likes the arrow and it tunes, shoot it. Adjust your sight for the difference and kill a deer.
PS, Cabelas is not a great place to buy archery equipment.

 

[MidMichBow]

GPI doesn’t really matter. Total arrow weight and how the weight is placed and used is what I think you are concerned with. The two arrows have different weight and the distribution of the weight is different. That will give different flight characteristics. Doesn’t mean one is wrong or better. If the bow likes the arrow and it tunes, shoot it. Adjust your sight for the difference and kill a deer.
PS, Cabelas is not a great place to buy archery equipment.

Yes, I found that out the hard way with Cabelas... I was hoping for a "quick fix" since I was down to 5 arrows but it was a mistake. The guy who "served" me didn't even check their online stock to see that they did carry the arrows. I'll be buying elsewhere in the future.

I appreciate your perspective.

 

[MidMichBow]

The small stuff would be which camo you wear or climber vs lock on vs saddle, etc. Arrow set up and tune is the exact opposite of the small stuff. Your bow and arrow set up is what does the killing. Accuracy and terminal performance all come from the decisions made around bow tuning and arrow set up. Not saying you should drop everything else and deep dive all things bow tune and arrow set up but would absolutely encourage you to start reading up on it and asking questions to start building that knowledge base.

Maybe the most the important two things to learn imo are spine and dynamic spine. Spine is the actual deflection or bend of the shaft with weight in the center, no fletching, no insert or point, just the shaft. Dynamic spine is how a fully built arrow is going to react when shot, force at the tail end of the arrow. GPI isnt totally irrelevant but it is one of the least important aspects of the whole equation. With dynamic spine, let's say you build an arrow with a standard insert and put a 100 grain head on it. The second arrow you use the same insert but put a 200 grain head on it. The second arrow is going to have a much weaker dynamic spine because it has a lot more weight in the front. You can also, to a lesser extent, impact things by decisions made with what goes on the back of the arrow. Take the same 2 arrows but put 100 grain heads on both. One you fletch with feathers only and a standard nock. The other you add a wrap, 3 vanes and a lighted nock. The second arrow is going to shoot stiffer or have a higher dynamic spine because it has more weight at the rear of the arrow. In those examples you have the exact same shaft with a stated spine and GPI but they will all fly different. Most folks wouldnt put a .308 round in a 30.06 and head to the woods but in some respect that's what a lot of folks do with their bow setup because they dont understand or appreciate the difference every component of an arrow build can make. Poor decisions lead to poor outcomes and the last thing any of us want is to be out there wounding or losing deer due to things we had control over. I 100% do not mean for this to come across like I am busting your chops and hope you take it with the good intentions I had for posting it.

I appreciate what you're saying. I'm here to learn - but I'm also just a dude who enjoys hunting as a hobby. Yes, I want to be competent; yes, I want to be safe and an ethical hunter. But I also have very limited time. I love hunting, but it's not at the top of my priority list. Everything you said is valid, and I appreciate your passion for archery. As I'm able and have time, I'll keep trying to learn. Thanks

 

[HawRiverArcher]

I appreciate what you're saying. I'm here to learn - but I'm also just a dude who enjoys hunting as a hobby. Yes, I want to be competent; yes, I want to be safe and an ethical hunter. But I also have very limited time. I love hunting, but it's not at the top of my priority list. Everything you said is valid, and I appreciate your passion for archery. As I'm able and have time, I'll keep trying to learn. Thanks

If you've never heard of him, Nate Sellers has a YouTube channel called Average Jack Archery. Nate owns a pro-shop in PA. He's also a pretty good target archer when he's not hunting. He talks a lot about simplifying setups and building bell-curve arrows. In other words don't get too lost in the weeds. Average 6.5mm arrows have killed more deer than any others over the years. They're cheap to build available anywhere and easily replaceable. You don't need to be an expert to get started or be a good hunter, but you do have to get out there and use your bow.

I've enjoyed all the tips and advice from forums over the years but also recognize that there's such a a thing as too much information. Too many opinions to weed through, too many keyboard experts saying their way is the best because they've been doing it since Moses first picked up a bow, and on and on. A lot of guys killed a lot of deer before we ever started arguing online about FOC, heavy vs Light, carbon vs Aluminum, flagship vs cheap bows, micro vs standard diameter. It's all just noise man. Don't sweat the small stuff until you're good enough to even notice the difference. You'll end up spending money on things that aren't going to help you much yet and spend more time calculating numbers than doing the one thing that will make you a better archer and hunter, shooting your bow.