ke/momentum help

[Mr Green 740]

All this talk about ke/momentum and all these calculations has me confused! Is there anyone out there who can figure out what im getting? I shoot a 60" Morrison ilf carbon/foam longbow limbs. 29" Goldtip xt hunter 600 total grain weight.(300 grain head,50 grain brass adapter) Balance point is 8 inches from the point. My setup shoots at 155 fps. HELP!

[rastaman]

Hey Mr. Green! i don't pay attention to ke/momentum numbers, but i don't hunt anything bigger than hogs and deer.  i shoot around 48lbs at 27 inches, and the deer and hogs don't travel very far.  i would say you have plenty of momentum which is more important than ke anyway.

[moebow]

155 fps and 600 grains is good for anything you're likely to be hunting!  You don't say what weight the bow is at you draw length but it doesn't really matter.

My 2 cents worth is that KE is a result of the compound companies' advertising hype and has little to do with archery or arrow lethality.  Momentum is what makes an arrow penetrate but again the actual numbers are pretty much meaningless to anyone but a mathematician or physicist.  What's a "slug" or an "erg" anyway??

The most usable rule of thumb is the old one that says that an arrow that weighs 10 grains (plus or minus a little) per pound of bow weight will do the job handily with a bow of reasonable hunting weight.

Don't get bogged down with these numbers.

[JimB]

I'm not very good with those formulas.I can tell you your arrows arw 22% FOC which is good.

You will notice that the experienced old timers here place little emphasis on formulas and a lot of emphasis on achieving great arrow flight,using adequately heavy arrows tipped with razor sharp broadheads and developing and maintaining the skill level to put that arrow in the pocket in the field,under pressure.

The KE formulas are poor predicters of penetration in real life.Momentum is where it's at.I can tell you this,you are shooting a 22% FOC arrow that weighs 12 grs per pound of draw weight out of a hunting weight,quality bow.If your arrow flight is good and broadheads sharp,you will have no trouble on any deer in North America,and most other big game.

[George D. Stout]

So what is bad?  8^).

[Predator Man]

your getting .4129 or I would round to .413 momentum.  27% foc.  This is very good. I use fred eichlers setup becuase he is the only guy I know who hasnt changed his equiptment in like forever and he has taken the super slam with the same setup.  He is somewhere close to .425 slug feet of momentum.  So you are good to go as long as where your going is not africa.

[Predator Man]

My deer setup is .350 momentum and im not worried about it getting passthrough's.  .300 and over for deer/turkey..... .400 or more for big north american game.... .500 or more for African big game.  

I have no basis for these numbers except for a post Dr.Ed put up saying he was getting exit wounds on african buffalo with .523 or .535

I then estimated fred eichler's setup because I know he can get it done on the big north american game.

I then calculated my setup for deer and there you have it.

[George D. Stout]

How about those Saints?  8^).

[Rob DiStefano]

Originally posted by George D. Stout:
How about those Saints?  8^).

ge-or-ge ....    

[Rob DiStefano]

Originally posted by Mr Green 740:
All this talk about ke/momentum and all these calculations has me confused! Is there anyone out there who can figure out what im getting? I shoot a 60" Morrison ilf carbon/foam longbow limbs. 29" Goldtip xt hunter 600 total grain weight.(300 grain head,50 grain brass adapter) Balance point is 8 inches from the point. My setup shoots at 155 fps. HELP!

tony, trust me on this - if yer arrows are flyin' well, your broadheads are sharp, yer consistently accurate at yer hunting distances, man you are good to go.

but if you must know foc and gpp ...

assuming your arrow is 29" from the depth of the nock to the back of the point, and your arrow balances 8" from the back of the point, your arrow's foc is 22.41% ... and assuming this is your 50# holding weight morrison your gpp is 12.

them's some mighty potent numbers, but reread my first sentence.  

thread cabin fever meter reading is 3 out of 10.  :D

[Predator Man]

OOOOps the guys are correct.  Your FOC is 22.41%.  I was guessing.... or not thinking.. or i dont know what I was doing.

[Predator Man]

Originally posted by George D. Stout:
How about those Saints?  8^).

I thing manning was paid off to throw an interception... he had poor foc on that pass.