Bitmasher:

I think I get the point of your questions. I think that you are interested in talking about the physics or science or philosophy of killing big game animals.

I understand the point about energy retained by a passed through bullet being energy NOT delivered on the target. If 1500 ft lbs of energy are retained by the bullet just prior to impact and the bullet passes through with a retained velocity of 200 ft/s and 80% mass, then something less than 1500 ft lbs of energy were delivered on the elk -- just wildly guessing, say 1300 ft lbs of energy is delivered on the elk and 200 ft lbs of energy is retained by the exiting bullet. Why is this better than the case where the bullet does not exit and hence all 1500 ft lbs of energy is delivered on the elk?

One of the posters, I think, suggested that the value of having a bullet exit is more related to making tracking easier than it is related to killing the elk. So this can be thought to be the prime virtue of the bullet passing through.

As another poster mentions, you want the bullet to retain mass and not break apart, because the bullet is more likely in this case to retain energy and penetrate deeply. It is by penetrating deeply that the best opportunity to maximize damage to the vitals is realized. As an extra bonus, if you bullet mushrooms, you cut a broader channel and produce more damage.

You could say that energy doesn't kill, it is deep penetration that kills. And a broader projectile produces more damage than a smaller projectile. For instance, I doubt that arrows kill elk because of the energy they have (that is, 1200 ft lbs of energy are not thought to be necessary to kill an elk with an arrow). I imagine they kill because of the cutting effect of the broadhead. The broadhead is able to penetrate deeply because it cuts through tissue. A bullet penetrates in a different manner -- it doesn't slice through.

Put all this together and it means you want a bullet which mushrooms but doesn't break apart. If it does this and it also penetrates all the way through -- then it seems to me you get maximal damage to vitals plus you get a good blood trail if you need to track.

I agree, but I don't see a complete passthrough as being necessary or sufficient for high killing effectiveness. Penetrating deeply, yes, but a passthrough, no.

Even breaking apart in and of itself is not inherently bad, it depends when it breaks apart. Breaking apart on impact is horrid, if it does it after passing through to the opposite rib cage, it really doesn't matter, imo.

Welcome aboard!

I prefer a "pass through" scenario called a through and through in the trauma circles, even though as bitmasher states it's not absolutely necessary.

The reason is that energy does not kill the animal. Disruption to vital organs or the central nervous system kills the animal. By passing through the animal I have a better chance at this tissue disruption over just making into the central core area. Of course if the projectile does not penetrate enough I have little to no chance at all. The extra blood trail is nice as well but irrelevant to the discussion.

The shock wave absorbed by the crew of an artillery piece constitutes several thousand fold more energy than that provided by a rifle bullet. The crews of these weapons do not die. They survive because this energy does not cause the necessary tissue disruption to cause death.

Energy simply drives the projectile. The projectile disrupts the vital tissues and that is how the death-causing trauma occurs. The temporary wound channel, as seen by bullets when fired through ballistic gelatin is ineffective as well. This temporary channel is caused by the shock wave as the energy passes through the organism.

Only if the temporary channel traumatizes necessary tissue will it kill. This is why a 9mm is less effective than a .45 ACP. The 9mm creates amazing temporary wound channels in gelatin. When a 9mm hit a body this channel is created inside the body as well. However, the displaced tissues will typically rebound back into position after the energy wave passes and only the disrupted tissue will remain, or have impact on the outcome of the shooting.

A .45 leaves a bigger permanent channel. A game bullet passing completely through the animal leaves a bigger permanent channel than one that does not. An expanding bullet again leaves a bigger permanent wound channel enhancing its ability to take down the game. How much tissue disruption is enough? This will vary so I attempt to always create as much as I can get. I like the insurance.

Ok, Tank you posted some good stuff.

I'm basically just rallying against the view that a pass through is important or critical to effective killing. Demanding a pass through, could lead to counter-intuitive results, because quick killing effectiveness is not a function of whether the bullet exits.

Ok, ok, I think you mean one thing but are saying something else, your examples I agree with 100% but I think your wording is misleading.

The disruption to organs comes from one source only, mechanical work (energy) done by the bullet on the tissue. Trying to seperate energy and penetration/wake-field is like trying to seperate the head from the tail of a quarter. They are both part of the same coin.

Excellent point. The reason is simple, the energy per surface area exerted or unit length is very low. If you took this same energy and put it all in a focal area of a 1/8" then the folks would unfortunately be hurting.

Energy of itself may or may not kill, how its delivered makes all the difference.

Now about the 9mm and 45-ACP, I think this is great info. In the case of the 45 ACP, it has 27% more surface area with which to deliver energy as it slides along the gelatin (and that assuming equal bullet lengths, the 45 ACP has a diameter of .451" and the 9mm .355", which if anything favors the 45 ACP even more, considering the mass of the bullets). This means that more energy is lost from the bullet and delivered to anything that resists it, because it takes more work to push it through (more surface area to slide along). This explains why the permanent damage field is larger than the 9mm, the increase in energy is going beyond the shear strength of gelatin for a greater length radial outward from the bullet.

The 9mm and 45 ACP is also a good example of why a pass-through doesn't mean much in quick killing effectiveness. Consider that both the 45 ACP and the 9mm enters an infinitely long gelatin slab at the same kinetic energy (yes one would have to tinker with loads of the two guns to accomplish this if it is even possible). Which bullet will stop first? The 45 ACP will without a doubt. The simple reasoning is that it has to dump more energy per inch of penetration because it has more surface area to push along (more friction) the column it bores out. Now a person might look at the two results and say that the 9mm is better because it penetrated further, but this is a bad assumption, because it ignores the greater amount of damage done over a shorter distance by the 45 ACP.

Welcome aboard Tankgunner.