diminishing returns

[rkelly]

Not looking for a scientific answer....
just common sense!

46# Bob Lee recurve
heaviest GPI in regard to penetration?

Not concerned with trajectory.

12 works good.
But what about more than that?

[-snypershot317-]

not sure if your asking about arrow weight or what but i shoot 55@28 and am currently shooting a 575-577 gr (pending on the arrow, due to some mixed shafts) which is just over 10gr/lb of draw weight and seems to hit like a ton of bricks...although i would like to get closer to 11 just outta preference but am happy with my setup due the accuracy of tune...just tune your arrow till it gets perfect flight with high foc, and you should be good to go seems how most shots are within 20 yds..hope this helps.

[JimB]

You can go to 13 or 14 easily,probably more.I just for kicks,I tried a 15 gr arrow on a 48# bow recently and can't see any problem and from the first shot,they hit the same as my other arrows.I was expecting some trajectory adjustment but there just wasn't any.I can't explain that.I haven't done any penetration testing with it yet but everything looks good.

[Orion]

You mean GPP (grains per pound of bow weight) not GPI (grains per inch of arrow length) right?  Regardless, you could go heavier, as others have pointed out, but at 12 gpp, you have a 550 grain arrow, great plenty for deer.

[rkelly]

thanks for repleys  yes orion  gpp was just shooting some 650 grain  was slower  than my 550 but thinking would i gain or louse pentatration on this pondage

[ozy clint]

i once did some chrono testing with my 69#@28" bob lee and found that momentum values started to go backwards at 1000gr arrow mass which is 14gr/#.

[Terry Lightle]

I am shooting 49# and shooting 700 grain arrows.Do not know how fast it is shooting,it makes me no difference.Have had lots of comments as to how quiet my bow is.

[rkelly]

ozy clint:
Thanks.  That was the kind of answer I was looking for.

[TxAg]

Here is the momentum formula if you want to check your set up.

Momentum = grains of arrow weight / (divided by) 7000 X (multiplied by) fps. Then divide answer by 32.

[Zradix]

I've found most bows are the most efficient around 12gpp.
..at least the ones I've test personally.

[Shawn Leonard]

Why? If you are hunting whitetail 8gpp. is fine and I find 9gpp. is perfect and you do not get a high arching trajectory after 20yds. I shoot 51-54#s and my arrows weigh 480 grains. I have my bows tuned to shoot the same arrow. Shawn

[JimB]

Here are some figures from one bow that I tested-53# recurve.
1.530 gr arrow,10 GPP,175 fps,momentum .41
2.619 gr arrow,11.67 GPP,165 fps,momentum .45
3.714 gr arrow,13.47 GPP,155 fps,momentum .49

Almost 20% momentum increase from the 530 gr arrow to the 714 gr.That's about the amount of penetration increase I see as well.