I'm shooting 53# at my draw length with 625 gr arrows. That puts me just shy of 12 gpp. I gain close to 20 fps if I go down to 10 gpp. I'm most concerned about penetration and consistency. There is a noticeably flatter trajectory with the lighter arrow that would allow me to feel more confident in slightly longer shots. I'm wondering when the added weight starts having diminishing returns due to significant loss of speed. I'd like to hear personal experience or knowledge about studies done on balance of weight and speed for hunting. Thanks.
10gpp at 53# will pass through any animal in North America so if you would like to drop arrow weight you will be in good shape!
I shoot 10.3gpp with a 50# at my DL bow. I get some complete pass-throughs, most with two holes and arrow falls out in the first 10-20yds, and once in a while just one hole if I get tied up in the off shoulder. I have personally seen a LOT of dead critters from this set up.
If you drop down to 10gpp you will not have any trouble with penetration.
Bisch
One of the more famous Fred Bear tests was when he built a frame packed with calf's liver and used a shooting machine to test various draw and arrow weights. Based on his results, he came up with the "Cipher Rule". He determined that a 60 pound bow shooting an arrow not heavier in grain than the bow weight with a cipher added and not lighter than 10% less (540-600grains). -Fred Bear "YE SYLVAN ARCHER-1943"
Later in life Fred said, "I think the archer should shoot whatever weight bow he might want to shoot, or might feel capable of shooting.....You cash in on the efficiency of the heavy bow only by increasing arrow weights. And in all hunting activities, I like to use a factor "nine;" nine times your bow weight for your arrow weight in grains. For instance, my arrows, 28 inches in length for my 65-pound bow, will run between 575 and 600 grains." -Fred Bear
So it appears to me, that ever since he conducted the shooting machine tests, his goal was 9gpp with a +/- margin, with 10gpp being a maximum ceilling. I think this works well with his recurve bow design.
Absent shooting the largest of game, where published testing talks about a weight threshold to maximize penetration, I think anyone following Bear's guidelines should have an ample balance between trajectory and penetration.
Best :)
An arrow can be stopped by a moving cardboard disk... Shoot at an animal that is relaxed and you'll get good penetration... If it's all tense and ready to bolt, well, figure it out... :dunno:
Other than that- 10-11 grains per pound is fine.
... mike ...
I am no expert but I say shoot the heaviest arrow you feel comfortable shooting.
Deer don't need much arrow weight. Stay off the shoulder and 8gpp. is fine even out of light bows. I have killed a few shooting a 42# Widow and an arrow that was 320 grains. Pass thrus on them all. I would go with the 10 gpp. if I were you, a perfectly tuned arrow flying perfectly staright and a sharp broadhead is much more important than a heavy arrow. Ecspecially on thin skinned game like deer and antelope. Shawn
I appreciate all the feedback. Bisch, I know you like hunting hogs as much as I do. I don't worry about our whitetail, I worry about our pigs. I like the trajectory of the 10gpp arrows I was shooting this weekend. I should still be able to run 200 up front with the tapered AD shafts.
Thanks again for the feedback.
Small pigs, no prblems. Big pigs with a shield can be problems. You shoot close to (but just a bit more) the same draw weight as me. I have found that an arrow into the shield of a big boar is a lost pig. The big ones you have to hit low and tight with the DW I shoot. It is actually a pretty small target on such big critters!
Bisch
Yeah, I'm amazed how small it really is. Last decent sized boar I shot had a heart and lung set only the size of my hand. And I have small hands. Luckily it was a perfect heart shot so he went down fast. Elevated stands make it even harder.
Even though I prefer heavier arrows myself, I think you found your best combination for you. The 10 gpp will for sure give you the penetration you want and also give you the flatter trajectory witch gives you more confidence like you said.
And keep in mind that even though many of us like heavier arrows, the great majority of trad hunters prefer a combination like your 10gpp.
The nice thing about this is that right now at this moment the 10gpp gives you everything you want and need and the extra confidence. If in the future you nedd or want something different its easy to do and you will know why you want to change based on your own reasons.
So I say go with what works best for you. Sounds to me like right now that is 10gpp.
Stupid phone...I hit reply before I was done....lol.
Last thing I wanted to add was confidence is everything. The 10gpp gives you that confidence. That combo will be just as deadly in 99% of situations in my opinion and if I was in your situation I would go with the confidence.
Personally, I shoot better with heavier arrow set ups than I do with lighter ones. I prefer 11-12gpp. That seems to work best for my instinctive style of shooting. At 10gpp or less, I have a tendency to shoot high, especially on targets 25 yards and beyond. With my current set up at 12gpp, I have been pleased with the cast of my arrows as they don't drop too much out to 40 yards, and I'll never shoot at anything but varmints and small game at or beyond that distance. Plus it makes my bows shoot quieter and smoother.
Arrow and bow weight are just part of the equation. Pay attention to your choice of broadheads on the tougher stuff. Long and lean goes deeper.
An arrow that is flying straight behind the broadhead will out penetrate an arrow that is flying loggy. One other minor point is that not all bows shoot all arrow weights the same. We compared several bows. The two that I found interesting was the Diablo and the Jack Howard. With 2114s they were close, with 2020s with heavy points the Jack Howard really showed its stuff, while the Diablo slowed down more with the heavier arrow. I would go for the straightest flying faster arrow if it was heavy enough to get the job done.
I think we make this stuff far more complicated than it needs to be, almost as if we think our gear is just barely powerful enough to bring down a deer. Some like the tinkering for the sake of tinkering, but the truth is that a wide range of arrow weights and a wide range of speeds can do the job.
The two things you must have are:
1. A sharp bh
2. An arrow that flies straight.
The rest of it is really quite subjective.
I like 'em light like my women. 10 GPP here.
If your goal is penetration, there is no balance. Go heavier. Penetration doesn't drop across any weight arrow you are likely to encounter.
The problem becomes trajectory. It's harder to be accurate across a rainbow than it is a flat field of vision.
If you take your bow..and run the numbers....starting at 8 grains per...and add 100 grains, you will see at some point a heavier arrow that WILL NOT perform better than the 100 grain lesser one. The speed will become so slow that it wont make up for the added weight.
Run the numbers for momentum and you will see.
Any idea how high do you have to go, Terry? I had this discussion with O.L. a few years back, and he was over 14gpi on one of his bows and momentum was still going up. Since that gave you a 1000 grain arrow in a 60 lb bow, I dropped the discussion. That's solid fiberglass arrow territory.
Terry, I'll have to run more extensive numbers than I did this past weekend to find the sweet spot. I feel good about the arrow flight with my AD lites and BH's in the no mercy 4 blades.
Ok here's my two cents since no one has mentioned it yet.
I gap shoot .... thats right ...say what you will. As a result, the faster the bow the bigger the gap and the longer the point on distance. at 155fps my point on is like 35-45yards depending on anchor point (nock at corner of mouth vs first finger at corner of mouth).
I try and keep most of my bows shooting around 140-150fps ... that usually means about 10-12gpp at my 25"draw length.
I'm sure lighter arrows would kill deer but I like having my bows shoot similarly in terms of gap. No other reason than that.
I'd like to keep the point on to 30yds to reduce the gap and have a point on that correlates to a reasonable max hunting distance ... .probably going to have to move the anchor point again though because too much arrow weight can also get ridiculous.
Sorry for the double post my browqser freaks if I try and edit ...
But to Terry ... I recently chronoes a 42# bow with arrow weights of 465gr up to 665gr ... so maybe 11gr/lb to 15gr/lb and the momentum and KE was still rising. I agree from a hypothetical standpoint that eventually you will see no more gains but you'd have to be shooting telephone poles.
I've only chronoed up to 14 GPP but at least up to that point,momentum was going up.
Here are some figures for a 51# Bear TD with Rose Oak limbs.
1.714 gr arrow,155 fps,14 GPP,momentum .49
2.619 gr arrow,165 fps,12 GPP,momentum .45
3.530 gr arrow,175 fps,10.39 GPP,momentum .41
Going from lightest to heaviest that's a 12.9% loss of speed and a momentum increase of 19.5%
Fred Bear did impact testing up to a ridiculous 18 GPP and found impact increase all the way up to there.But,he liked 9-10 GPP,because of the balance that we are talking about between trajectory and penetration.He also took very long shots at game,at times.
I think you just have to decide where your personal balance point is and what kind of trajectory you need or like.
Zane, you probably already know this but just in case someone else would like to see it, here is the momentum formula to check your set up.
Momentum = grains of arrow weight / (divided by) 7000 X (multiplied by) fps. Then divide answer by 32.
It is also about where the weight is. I think it is better up front than if it gained via some sort of weight tube. But a razor sharp head flying on a finely tuned perfectly straight flying arrow trumps everything else.
I listened to some audio of Ed Ashby speaking at the P+Y convention in Dallas(On tuffhead.com)and he was asked about what his findings were on diminishing returns.He said that on straight limbed long bows they found it at about 10 GPP but on highly efficient hybrid bows it could be at 15-16GPP.
He also reminded people that diminishing returns does not mean there is no increase,just that the increase slows down.It wasn't that long ago that I used to think it meant the increase stopped or went backwards,but I learned that that is called negative returns.
There are both audio and a couple videos from the talks,over at Tuffhead.I would like to have been there.It would have been nice to throw out some questions.
Guys I'm really enjoying the conversation. I appreciate that for the most part people on this site can have different opinions and yet find value in others' perspectives. It's a pleasure to just listen to guys with great experiences. Keep em coming