After much study, I believe the over-penetration issue to be a bit hyped.
Because of the elasticity of the outer skin, a bullet penetrating the exiting layer of skin is equivalent to penetrating four inches of flesh. That is why, if you study many shootings, so many end up with the bullet sitting just under the skin, on the opposite side of entry. Many bullets make it to the last layer of skin and stop there because they don't have the juice to exit that last layer of skin.
Think about it: First, you can add 4 inches to any penetration you think is too much. Look at the shallowest cross section of the torso and you've got about 8 inches of meat and bones. (Oh yeah, let's not forget about bones). Anyway, not even considering bones, on a perfect frontal shot, the bullet has to pass through at least 8 inches of meat minimum, and then exit the skin, which is another 4 inches. That is 12 inches of penetration before you have to worry about the bullet even exiting the body. And, let me remind you, that is a very MINIMUM standard. Many people are thicker than that, many criminals are often dense and muscular, that number also does not account for bones, and that is assuming a perfect frontal shot with no obstructions. In other words, that is a *very* basic and minimum number and only for a perfect frontal shot. Add any angle in there or obstructions and the needed penetration grows quickly. And, I don't know about you, but most of the places I aim on the body are surrounded by thick bone, which can slow a bullet even more.
Lastly on that issue, not only does the bullet have to have enough juice to exit the body, it then has to have enough juice to penetrate another body and deal serious damage to an innocent person! So, not only does it have to penetrate a *minimum* of 12 inches, but then it has to have enough juice left over after that to fly through the air and penetrate someone else another few inches at least, in order to hurt them.
Also, gelatin is not, and never was, considered to be equivalent to flesh. Gelatin testing just guves a reference point for how a round will perform relative to other gelatin tests. Just because a bullet penetrates 12 inches in gelatin, does not mean it will penetrate that deeply through someone's chest.
I just think the issue is over rated and is another reason to sell articles and test ammo (so you have to buy the latest ammo design).
I know for a fact as a former EMT that I have seen .45 hardball bullets NOT exit the body, multiple times. If hardball does not overpenetrate then I have good faith that most any .45 hollowpoint will not.
And yes, cops average hitting their target 1 out of 8 times (12.5%).
Seeing cops shoot, that is not a surprising fact. They are, overall, HORRIBLE shots. I mean, on the range, in the best conditions, they can't even hit a sillouette target at 7 yards much of the time. I mean, they miss the whole target! That is with no stress! I really think that the public, and departments, should DEMAND that Officers be more competent with their guns before they send them out on the street. It is a danger to the public, how bad most of them shoot.
And the thing is, not to bash them, but if they miss the target, the department gets sued, not them, so they don't have that much driving force to become better shots. There is no penalty to them personally if they miss and hit someone else, because the lawsuit goes right for the deep pockets of the department, not the underpaid cop.
Many overpenetrating cases sited are cases where the bullet passes through an arm, or a peripheral tissue, like 3 inches, and goes on to hit someone else. I have never heard of anyone that has hit COM and had a standard hollowpoint round (like .40) go through and hit someone else with serious effect. If the cases do happen, how often? What are the odds? Everything is an odds game, and unless the odds are significant that it could happen, then it is just not on the top of my list of concerns.
Now, this is assuming standard pistol rounds. When you get into the magnum rounds like the 10mm, then you better stick with the lighter bullet weights, because the 10mm with a 180gr bullet WILL go in and out of a person and still keep going with plenty of juice to kill another person.
[This message has been edited by Red Bull (edited November 19, 1999).]