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I was discussing bullets going all the way through an animal verses one that stays in then animal with a friend. He thinks the bullet that stays in the animal has transferred its energy better. I think it may just mean it did't have enough energy to go all the way through. Most of the moose that I have shot the bullet went through the lungs and both sides never to be found. In all those cases the moose went down and never got up. What do you think?
 

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Yes, of course! but that's not all bad. You seldom knock down a big animal with a lung shot or any good chest cavity shot since there's less to stop the bullet and absorb the total energy. Also complete penetration depends on the total bullet hitting energy and bullet construction. A 35 Rem might not penetrate all the way through and dump all of its energy; that's why deer often crumple up with that slower 200 grain bullet stopping inside. A 45-70 heavy hard cast bullet might completely penetrate and knock down the animal with a shoulder hit. A bone hit will more often stop complete penetration, depending on the above, and that's something you might want to break down a big bear etc with a shoulder hit. On elk and moose an old hunting guide I hunted with many times says that the best sight he sees at the shot on an elk or moose on a cold morning is to see 'steam' coming out both sides of the animal, then he knows it is as good as down.
 

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I would say if your shooting the same grain bullet out of the same caliber gun, then you are strictly comparing bullet design ... and the one that stays in the animal has dumped all of its energy through expansion.
 

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I don't think there is a standard patent answer for the question.

With regards to energy transfer, I think it is a matter of shot placement first. The hydrostatic-shock imparted, the temporary wound channel, the permanent wound channel, the efficiency of the means of the energy transfer, the meplat of the bullet, the expansion of the bullet, the temperment of the critter being shot, the initial kenetic energy available for transfer at the impact, etc. all play some part in the question of energy transfer, but are secondary to shot placement.

One undeniable truth of complete pass-through penetration is that there are then two holes from which the critter will leak, instead of just one; regardless of the amount of energy transferred.
 

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Slime green cat said:
I would say if your shooting the same grain bullet out of the same caliber gun, then you are strictly comparing bullet design ... and the one that stays in the animal has dumped all of its energy through expansion.
I agree with this 100%! I don't think any hunting bullet is actually designed to pass straight through any animal you are shooting at. Solids are designed for more penetration on bigger animals a larger animal needs a bullet to penetrate deeper to reach the vitals or break through thicker bone and tissue. I think if a bullet was made for maximum penetraion but also made not to pass straight through the animal every PH on earth would be using it and this is what most companies making ammunition are trying to achieve. This is close to impossible as every situation is different depending on the size of the animal and where the bullet hits the animal. Long story short a bullet that passes straight through can still be affective but a bullet that remains inside the animal with enough penetration should be more affective.
 

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DWB said:
One undeniable truth of complete pass-through penetration is that there are then two holes from which the critter will leak, instead of just one; regardless of the amount of energy transferred.
Not only that, pass through bullets are transferring energy all along that bullet path, and doing damage as they go.
 

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Hi Bluedodgeman,
If you check the Garrett site you will find an informative write up on the subject of bullet penetration/speed. It may answer what you are looking to find.
 

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I like to have an exit wound.
The bullet that exits has dumped energy into the animal, hydostatic shock. A bullet through the lungs that exits will cause the lungs to collaspe due to the pressure drop making for a quicker kill.
Also having enough bullet mass and speed will ensure enough penetration should you have a hard angle, your bullet will reach the vitals. Exits also allow for more blood to leak out should you have to trail a wounded animal.

JD338
 

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Awww the two bullet therory again, one that penetrates all the way making two holes and the one that stays in the body. Sure more energy is felt in the animal being shot if the bullet doesn't exit. It all amounts to where they are hit and what internal organs are damaged or how much bleeding. I aim for tagging the animal on the spot and usually do and rarely have to track very far, but bad things can and have happened. I sure like to spine shoot elk and break their backs, but I have seen some mature bulls and cows that did not want to stop and will drag them selves a long ways. Shoot untill they are down for good.
 

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An interesting question with an obvious answer...any energy remaining in the bullet after exit is spent in the dirt or he brush beyond.
But come on guys... really, who cares?
A properly placed shot with an appropriate caliber and bullet weight is going to do the job intended.
I've never recovered a cast bullet from a 30-30 or 45-70, and critters hit have been DRT.
I won't loose sleep wondering about penetration...
 

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As far as I'm concerned, the key to dropping a critter very quickly is to have your bullet penetrate to the vitals while doing a lot of damage to those vitals as it goes. The idea that a bullet that doesn't exit has deposited all its energy in the animal and is the best way to go is basically flawed. As an example, a bullet that does not hold together well may deposit all its energy in the animal but not penetrate to the vitals. That's a ticket to having a game animal run off and get unrecovered. But, just having a bullet penetrate all the way through the game animal is not the whole answer either. A full metal jacketed bullet very likely will penetrate all the way through a deer, for example, without destroying a lot of tissue in the vital organs and putting it down. That's why they are illegal for deer hunting in every jurisdiction that I'm aware of.

The ideal hunting bullet is one that will expand, destroying vital organs, busting through bone, and then penetrating all the way through, exiting so as to have the animal bleed out and to leave a good blood trail. Nowadays, we are lucky in that we have available to us a number of bullet designs that will accomplish this, even in factory loadings.
 

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Ok back to common sense again, if a bullet stops inside the animal it has expended 100% of its energy into the animal. If that same bullet were traveling just a little faster (the animal was closer to the shooter) and exited the animal it would have not expended 100% of its energy into the animal, but it would have expended more energy into the animal than if it were traveling slower and stayed inside the animal. By traveling faster and therefore further into or through the animal, it would also create more tissue damage and therefore be lethal more quickly.
 

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Okay, let me ask this....

If a 405 grain bullet from say a 45-70 is going a mild 1000fps and does not make it through a deer, well no that is hardly possible, lets say does not make it through an elk but stops short of the ribs on the far side. It has expended whatever energy a projectile of 405 grains at 1000 fps has to offer right?

Now, if that same bullet were going say 1900 fps and blew through that elk but used only the energy of a bullet going say 1600 fps to get through the elk and the last 300fps of energy was "wasted" in a tree or in the dirt would you say that the first bullet imparted more energy to the elk than the second? NO! For that matter, if you could make that bullet go 2100 fps it would impart more energy to the elk than the one going 1900 simply due to more energy available. It's not just about pass through or no pass through. It's also about how FAST it goes through, how much resistance it encounters, how fast it decelerates and how much disruption it causes in the time it is passing through. You'd have to get pretty deep into the physics of what is going on to really figure it out.

The only way complete penetration means less energy transfer than a pass through is if you are shooting the same bullet at the same speed but hit different stuff in the critter. Take two 1600 fps 405 grain bullets that both hit an elk in the chest but one catches both shoulder bones square and does not exit while the other hits nothing but a rib on one side blows on through. That would be an example of a pass through transmitting less energy than a bullet staying in the animal but it is due to an adequate load encountering maximum resistance. If you start changing speed or bullet weight and getting velocity up there a bit higher, you're gonna do a whole lot more damage even if the bullets pass through every time. Loading down so that a bullet stays in the critter on purpose is simply reducing available power and to me is totally pointless. Now, if you are talking about little bullets like a 223, 243, 22-250 etc blowing up and not exiting then yes it is effective because there is so much energy there and there is massive disruption in the bullet path. But with a 45-70??? Doesn't really apply. That heavy, slow bullet is in a whole different league.
 

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Dave, very good, I think you got it.
 

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Dave Bulla said:
Okay, let me ask this....

If a 405 grain bullet from say a 45-70 is going a mild 1000fps and does not make it through a deer, well no that is hardly possible, lets say does not make it through an elk but stops short of the ribs on the far side. It has expended whatever energy a projectile of 405 grains at 1000 fps has to offer right?

Now, if that same bullet were going say 1900 fps and blew through that elk but used only the energy of a bullet going say 1600 fps to get through the elk and the last 300fps of energy was "wasted" in a tree or in the dirt would you say that the first bullet imparted more energy to the elk than the second? NO! For that matter, if you could make that bullet go 2100 fps it would impart more energy to the elk than the one going 1900 simply due to more energy available. It's not just about pass through or no pass through. It's also about how FAST it goes through, how much resistance it encounters, how fast it decelerates and how much disruption it causes in the time it is passing through. You'd have to get pretty deep into the physics of what is going on to really figure it out.

The only way complete penetration means less energy transfer than a pass through is if you are shooting the same bullet at the same speed but hit different stuff in the critter. Take two 1600 fps 405 grain bullets that both hit an elk in the chest but one catches both shoulder bones square and does not exit while the other hits nothing but a rib on one side blows on through. That would be an example of a pass through transmitting less energy than a bullet staying in the animal but it is due to an adequate load encountering maximum resistance. If you start changing speed or bullet weight and getting velocity up there a bit higher, you're gonna do a whole lot more damage even if the bullets pass through every time. Loading down so that a bullet stays in the critter on purpose is simply reducing available power and to me is totally pointless. Now, if you are talking about little bullets like a 223, 243, 22-250 etc blowing up and not exiting then yes it is effective because there is so much energy there and there is massive disruption in the bullet path. But with a 45-70??? Doesn't really apply. That heavy, slow bullet is in a whole different league.
YOu took more words than me...

mogwai said:
Not only that, pass through bullets are transferring energy all along that bullet path, and doing damage as they go.
But you did a better job of explaining it. Great job, in fact.
 

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All this talk about bullet energy completely misses the point. The goal for any bullet design at any velocity is to expand causing tissue destruction in the vital organs of a game animal. The more tissue destruction in the vitals the better. The only advantage of a bullet exiting the animal is to provide an additional hole in said animal to assist in its bleeding out and to make for a better blood trail for tracking it if it isn't DRT.

Take for example the .30-30. The amount of energy expended by the .30-30 bullet at its normal velocity is sufficient for it to penetrate through the vitals with sufficient expansion to get the job done. But, if that same bullet is fired from a cartridge that has a muzzle velocity of say 3,000 fps, It will hit the animal with more energy than the bullet fired at typical .30-30 velocity. But the result is liable to be excessive expansion and more damage on the surface of the game animal without sufficient ability to get the bullet through the vitals.

So, as I see it, the amount of energy expended that is required is for the bullet to expand and penetrate through the vitals while causing great damage to same except for some dangerous game like Cape Buffalo where solid bullets are used to provide for the deepest possible penetration through the vitals without any consideration for expansion.
 

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Personally I want a hole in both sides.I don't care if I find a nice pretty mushroomed bullet, as long as the animal is down that is my main concern.Any energy wasted after the bullet passes through the animal does not matter.Two holes are better than one.
 

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Exactly right Brian, bullet energy is more than a measure of penetration power, this total bullet energy measure also includes rotational energy. Bullet companies report foot pounds of energy because it increases more dramatically with bullet velocity increases than momentum does. The faster you push a bullet through a barrel with rifling, the faster that bullet will spin. This rotational velocity of the bullet does not significantly increase penetration. Although this spinning energy does add to bullet stability, it also increases drag friction which slows the bullet to some minor degree. It is momentum that is the primary measure of a bullet's penetration abilities (excluding bullet expansion effects). To look at this mathematically, the formula for Energy is: E = mass x velocity x velocity. The mathematical formula for Momentum is M = mass x velocity. So you can see in the world of capitalism where profit (cash) is king, the sales principle used here is "sell the sizzle not the stake".
 
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