Blain

Sure we all know that both contribute to muzzle energy, and knockdown power and all of that. However, I have heard, and suspect this to be true, that a heavier bullet at a slower velocity that equals in footpounds to a faster bullet of a smaller mass will have more of an effect on a target.

Now of course it could also be the other way around, and some have argued that it is. The question is from your own thoughts and experience what has more of an effect on a target, because even though the footpounds are the same, the weight and speed of the bullet is going to determin the wound potential and knockdown energy.

Example:
400 grains at 1900fps= 3,206 ft/lbs
vs.
150 grains at 3103fps = 3,206 ft/lbs

So which is it? Weight or speed, lets us know what you think and why. Which above bullet weight as listed in the example would be better and why.

From Squirrel to Elephant, the Shotgun is your gun.

tussey mountain hunter

I would say that in all probability, the heavier bullet would probably be more effective on heavier game, and the lighter bullet on lighter game.(Although shot placement is the most important factor)
My logic is that the big, heavy bullet would really give a knockdown womp to the animals, and generally since heavier bullets have bigger calibers, they create a bigger hole in whatever they are aimed at. The lighter bullets for lighter game is because the shock of the bullet would be great, and that would do much damage to the animal. I would imagine that shock would have less of an effect on heavier game(such as grizzly bear) than it would on lighter game(such as deer)
That is why I would elect the shock of lighter bullets as the best light game getter, and the large hole for bleeding and a real wollop for heavy animals.

tussey mountain hunter

I have one question for you though, how do you get the foot-pound for a cartridge? I see you have done that here for your example.

RNZ

I took a firearms personal protection course and saw an 1 1/2 hr. video on ballistics. Under controlled lab conditions, the heavier slower bullet will penetrate farther than a faster lighter one. The foot pounds generated by a bullet have little effect on the target. The placement of the round, meaning how much important tissue it destroys, is more important for getting a quick kill. Obviously bigger bullets make bigger holes which means they have the opportunity to destroy more tissue and cause more trauma. Also since heavier bullets penetrate farther they have a better opportunity to destroy vital tissue that a faster smaller bullet generating the same force may never reach. That's what the US army lab basically concluded in this video.

Colo Wolf

Years ago, John Taylor did a mathamatical thing called knock out value. He used the bullet weight times diameter times velocity then deivided by 7000. That would give you a number such as the 7mm mag of 21, the 243 at 13 30-06 was 22 or something like that. This formula would give you an idea of how truly owerful a cartridge was / is. A big fat weighty bullet would be the winner everytime.

Reality is this though, create a sucking chest wound, the animal goes down, lose enough blood, the brain dies, and the meat is yours.

Blain

The formula for determining muzzle energy in footpounds is, Mass times velocity squared divided by 450436.

(M*V^2)/450436

Of course mass is the bullet weight in grains and velocity is in feet per second.

I too also agree that the larger diamater of a bullet seem to translate into more "knockdown" power and greater terminal effect than a lighter, faster bullet. Though I think that a larger bullet would be more damaging on both small and large game than a faster one. Just how it seems to figure out to me.

From Squirrel to Elephant, the Shotgun is your gun.

8mm/06

Rather than trying to decide which size and speed bullet is better than the other, it is more advantageous to determine the correct size and wieght bullet to be matched to bullet construction. I could effectively use both a 125 grain bullet and a 220 grain bullet from a 30/06 to kill a decent sized whitetail. I would want the 2 bullets to be of different construction in order to do the appropriate job on the animal. Small and fast but thinly jacketed is good for little but varmints and huge and slow but in a solid construction doesn't do the trick in every situation either.
Speed and wieght must be matched to bullet construction and to the job at hand.
All the other theory is interesting and probably useful in determing mathematical fact, BUT Colo Wolf wins the prize for the most pointed remark because "create a sucking chest wound, the animal goes down.." is simple but true.

Edited by - 8mm/06 on 01/03/2002 19:19:20

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Alaska Dave

That CO. Wolfs reply sent shivers up my back. I always have prefered a heavy for caliber bullet in my rifles. I always appreciated it when the bullet went through the intended incase the shot went bad. One of the most comforting sites that ever passed across these eyes was the spray of lung blood on nearby vegatation.

8mm/06

akhunter,
I would have to agree with you about the "freight train" effect. Although it doesn't necessarily have to be in the very heavy weights yoou mention. Even a smaller caliber like a .264 can get a "freight train" effect if you push a heavy-for-diameter bullet out of the barrel. The 160 grain bullet, while not particularly heavy, is quite heavy for the .264 diameter and has a long profile...it provides tremendous penetration. BUT it ain't no 500 grains!!! Any 500 grain bullet that finds its mark with 2200 fps is going to provide some world of hurt!