How much energy (foot pounds) to kill a deer?

Without good placement of an appropriately designed bullet, energy doesn't mean much, let me rephrase that, energy doesn't matter. The size and placement of the hole is the entire story, as Dogleg said some time ago, its the amount of sunlight you let in.

Decide what you need and use it. If a .243" bullet that expands to .45" and penetrates 12" is enough, the animal will die. If a .45" bullet that doesn't expand but penetrates 5' is suitable for the size and density of the target, the animal dies. The speed by which the animal's brain is deprived of it's supply of oxygen rich blood determines how quickly it dies, not the energy expended to make that happen.
 
There is a lot of misunderstanding in this thread. Penetration has nothing whatsoever to do with kinetic energy. Penetration is determined by bullet construction and velocity; kinetic energy is determined by bullet weight and velocity.

At a given velocity a solid will penetrate much farther in any medium than an expanding bullet of the same caliber and weight. They will both have the same energy if they have the same velocity, but bullet construction will determine relative penetration.

Actually, any given bullet will tend to penetrate the most distance at a velocity of about 1600 fps to about 2000 fps. As you add velocity beyond those levels, penetration will actually decrease.

A .22-250 has about 1600 ft/lbs of kinetic energy at the muzzle. A typical 45-70 factory load has about the same kinetic energy. Which do you think will penetrate further into a moose or grizzly perhaps?
 
H4831 said:
Not many foot pounda of energy in a 22 long rifle, like about 120, but lots of deer have been shot with the 22lr. I have seen two so killed.
I have even seen a large whitetail buck that was killed with a 22 with shorts to the lung area.
I helped butcher it.
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Natives here in Manitoba regularly shoot at moose with 22 rimfires. Put a bunch through the lungs and sit down for tea. Moose are supposed to then walk of and lay down for an easy kill later. Through the years we have taken many bulls will 22 slugs and holes through the rack. I would imagine they do the same with deer as well. But back to the OP, it is generally said that 1000 foot pounds is required to kill deer humanely.
 
Look up 50cal deer hunting on youtube. There is an exit hole the size of a watermelon and it still runs a good 50 - 100 yards. Actual energy contained in the bullet has little to do with it. Energy has to be enough in for a given bullet type to penetrate approx 3/4 of the way through a given target animal to cause enough damage to kill quickly.

So for an "average" deer I would say 450 - 500 foot pounds for a .25 - .35 cal bulllet of expanding design, give or take. When I was a kid I took a deer with a 22lr at about 10 - 15 feet, but that was a head shot, shooting down-ish.

The standard answer is 1000 ft/lbs. I think this is because the 30-30 is the gold standard in deer rifles and that is about what you can expect froma 30-30 round, so all others are judged against it
 
i still have my hunters course manual from 1980's. It says :
deer: 900 ft. lb minimuim, 1200 adequate, 1500 preferred.

I personally shoot sabots at about 1200 and thats plenty. Shot placement
in the lungs, heart or any vitals and they wont be running too far.

FYI, moose:

2100 min, 2800 adequate, and 3500 ft. lb preferred.
then again, ammo has come ALONG way since then.
 
Trotter said:
i still have my hunters course manual from 1980's. It says :
deer: 900 ft. lb minimuim, 1200 adequate, 1500 preferred.

I personally shoot sabots at about 1200 and thats plenty. Shot placement
in the lungs, heart or any vitals and they wont be running too far.

FYI, moose:

2100 min, 2800 adequate, and 3500 ft. lb preferred. then again, ammo has come ALONG way since then.
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LOL, I guess all those moose shot with the venerable old 30-30 and similar chamberings did not recognize this.

I hunted with a close friend for years whose only firearm at the time was a 38-55 Winchester.
He did not reload, and Winchester factory ammo has trouble making 1200 fps with that 255 grain SP bullet.

The deer and moose all died.....usually one shot, and it was time to roll up the sleeves.

If it makes one feel more confident packing a hand-held cannon that lays the daisies low on a ½ acre plot, I'm all for him.

But those who assert that you MUST have XX amount of energy to humanely take some game animal, I say: get a life! ;) :D

Regards, Eagleye.
 
No one said 'must' only recommended.
Remember - speed is not a synonym for energy.

For example, the Hornady's 30/30 165gr Leverevolution has 1650lbs of energy at 100 yards and is moving at 2150 ft/s.

Shot placement is great. Having the animal absorb the entirety of the bullet's energy doesn't suck either.
 
tjhaile said:
Kinetic energy doesn't directly correlate to wounding effect well enough to make a good rule of thumb. Projectile construction is much more important.
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Kinetic energy relates strongly to wound volume. A wound can be short and wide, or long and narrow and have the same volume, so penetration is the result of other factors, but the volume of the total wound channel is energy related.

I think most of us know the difference in hunting consequences to a short wide wound channel (very frangible bullet) compared to a long narrow channel (a solid bullet's behavior on the extreme end).
 
However many foot pounds it takes to drive your bullet well into the vitals is enough.

I was just asking myself this sort of question this weekend actually.

I was looking at some recovered .224 dia 52gr TSX BT that I had shot from my 22-250; they had expanded perfectly to right around .43 cal, and had four nice, sharp petals just like they should. I couldn't help but thinking that one of these in the boiler would be just fine to kill a moose (it's moose season here, so I've got them on the brain). I know it's not legal, and I would not try it, or reccomend it, but that nasty little bit of bullet technology I was holding gave me the definite feeling that it could handle moose just as well as coyotes, so long as the hunter did his part.

If I lived in a deer hunting region, and it was legal, I'd certainly hunt deer with a 22-250 with said TSX's, and energy ratings be damned.
 
rral22 said:
Kinetic energy relates strongly to wound volume. A wound can be short and wide, or long and narrow and have the same volume, so penetration is the result of other factors, but the volume of the total wound channel is energy related.

I think most of us know the difference in hunting consequences to a short wide wound channel (very frangible bullet) compared to a long narrow channel (a solid bullet's behavior on the extreme end).
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Not necessarily. Given the same kinetic energy, a slower, larger projectile tends to crush more tissue and stretch less tissue compared with a smaller, faster one. Scroll down about a third of the way here and click on the links to figures 4 and 7 to compare:

http://www.rkba.org/research/fackler/wrong.html

The only way to meaningfully evaluate terminal effect is to compare wound channels in a suitable medium. Given adequate penetration, a larger wound channel will cause more rapid blood loss, leading to more rapid incapacitation.
 
tjhaile said:
Not necessarily. Given the same kinetic energy, a slower, larger projectile tends to crush more tissue and stretch less tissue compared with a smaller, faster one. Scroll down about a third of the way here and click on the links to figures 4 and 7 to compare:

http://www.rkba.org/research/fackler/wrong.html

The only way to meaningfully evaluate terminal effect is to compare wound channels in a suitable medium. Given adequate penetration, a larger wound channel will cause more rapid blood loss, leading to more rapid incapacitation.
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You are correct. But what I said was that it correlated - not caused or matched. There is, in fact, a strong correlation between bullet energy and wound channel volume. Any given bullet will produce more wound volume (but not necessarily penetration) if you drive it faster.

That does not change the fact that bigger bullets, of the same kinetic energy as a smaller bullet, will enlarge the wound channel as you have pointed out.

I disagree somewhat with your last paragraph in that I don't think wound channels in any test medium will be a reliable predictor of bullet effects on game. Again, I would expect some correlation, but only some, simply because there is no really good test medium. They are all just gross approximations of real game animals. I test lots of bullets in various media, and I do think "comparisons" in a specific test medium can be helpful, but hardly definitive. It's kind of fun too. ;)
 
jethunter said:
Actually bullets kill deer, not foot pounds.

In mathematical terms we can express the energy needed as a function of the square root of fA:

D=Bp*Bd
....(Be)
..
where D= dead deer, Bp=bullet placement, Bd=bullet design, Be=bullet energy, fA=f**k all

Using this formulae it is possible to quantify energy requirements as follows: for a brain shot approximately 50 ft pounds from a 22 lr will kill a deer, but to kill a deer by shooting him in the ass will take approximately 18,000 foot pounds from a 88 mm howitzer.
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LOL. Best answer here!

Bulsh!t question / multiple bullsh!t answers= questions/answers

That actually may be the equation for this whole site...
 
5440fight said:
LOL. Best answer here!

Bulsh!t question / multiple bullsh!t answers= questions/answers

That actually may be the equation for this whole site...
Click to expand...

simplified expression: BS IN = BS OUT

You're the only one who had the marbles to grasp my mathematical expression.
The "square root of f**k all" is a very small number. :D
 
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