32lbs ke enough for hogs, or deer?

[pokeanhope]

I just put my hunting set up in the kenetic energy calculator, and came up with 32lbs as my best bow/arrow combination. I am shooting a 612grain arrow at 155fps, I have a 515, and  475 grain setups also, but they do not shoot fast enough to make up the diffrence in lack of grains. So my question is this engough to kill small hog, or a tennessee deer? This is out of my 50lb recurve, the one i shoot the best.

[TxAg]

Yes, you won't have any problems. Happy Hunting!

[Col HJ]

A much better gage of a bow/arrow combination is that of momentum (velocity x weight/7000),KE is important to a rifle hunter that is trying to cause shock via energy transfer - we are trying to get penetration and momentum beats KE all day. Your set up is fine.

[Ragnarok Forge]

Should work fine.  Get close, shoot straight, make meat.

[Cmalone1]

Col HJ is that the formula for momentum?

[Col HJ]

Yes sir! The basic formula is mass X velocity but to get manageable numbers we divide by the constant of 7000. The kinetic energy formula squares the velocity which is the folly in using KE to measure a bows effectiveness, an 800 grain arrow at 180 fps from a stiff longbow or recurve will give adequate penetration on most anything but a 450 grain arrow smoking along from a modern compound is liable to be marginal, really marginalon anything tough. I made a perfect hit on a big hog with a 425 grain arrow from said fast compound and....no picture. My bud and I trailed him to his bed where he rose the next morning, all bleeding stopped and he appeared completely unaffected. Momentum is where it's at, my smallish wife is shooting 700 grain arrows from her 50# compound and they rock the target bag with authority.

[Cmalone1]

nice!! I put in all my info into the momentum calculatoer...what is a good range for the momentum?

[Col HJ]

I am a bit of a horsepower nut, liking heavy draw weights and heavy arrows...having said that a momentum factor of maybe 11 or 12 is probably a good minimum for deer and smallish hogs. I

[Dr. Ed Ashby]

In both the KE and Momentum formula the mass of the arrow must be in pounds. In each formula the product of the multiplication(s) must be divided by the Gravitational Constant (Gc). The Gc is 23.174 feet per second per second.

The correct formula for an arrow's momentum is:

Mo = Mass in grains X Velocity in fps divided by 225,218. The answer will be in Slug-Feet/Second,

(225,218 is 7000 X 32.174.  The 7000 converts grains to pounds, which is then multiplied by the Gc.)

For what it's worth, the formila for KE is:

KE = 0.5 X arrow mass in grains X the arrow velocity in fps squared, divided by 225,218.

As with the momentum formula, 225,218 converts the weight in grains to pounds and adjust for the gravitational constant.

As for what is a good number for momentum, that can depend on arrow setup. I'm routinely getting exit wounds on Asian buffalo with an penetration enhanced EFOC arrow setup at 790 grains and 28% FOC with 0.523 Slug-feet/Sec of momentum, and just under 39 foot pounds of KE.

Ed

[Col HJ]

And just when I think my pea brain is onto something.....Dr Ed I have a similar setup to you, 700 gr arrows with 26% FOC and certainly I'm hoping for similar results on Buff in OZ this summer. I haven't chrono'ed my setup but there rocking pretty good with 80# draw weight.

[Dr. Ed Ashby]

Col, if its tuned well you can expect, at the minimum, a solid double lung hit, and likely a complete thorax traversing hit, from any reasonable shooting angle ... even on a big bodied, trophy class bull!

Have fun! There's not much that compares with buffalo hunting.

Cheers,
Ed

[dick sable]

WOW!!!!

[Predator Man]

Wow is correct.... calculating my setup now.  DR ED... can you give us some numbers we should shoot for for deer/elk/moose?  This momentum thing is new to me.

[Predator Man]

So my deer/small game setup is giving me numbers of .335 momentum and 35 ke.

[razorback]

Dr Ed, which Gc is the right one 23.174 or 32.174. Looks like you transpossed numbers in your earlier post, i do that all the time with phone numbers.

[Predator Man]

Originally posted by razorback:
Dr Ed, which Gc is the right one 23.174 or 32.174. Looks like you transpossed numbers in your earlier post, i do that all the time with phone numbers.

Good catch, hope he responds!

[Dr. Ed Ashby]

Thanks, the correct Gc is 32.174.

Ed

[Maxximusgrind]

Wow,I am in the presence of smartness....But dang it,Now theres math to do..
   Robert

[michaelschwister]

Dr Ed has broken the code on this issue.  His work is the Magnum Opus on arrow lethality

[Maxximusgrind]

Deffinately,
 His work changed alot of what I thought I knew.I am verry thankful that he has shared his work on this with us.
 Robert