But since pistol bullets inflict injury not by energy transfer, but by physical penetration and direct (crushing) destruction of tissue, the comparison with a _base_ball holds all the water it needs for this discussion. It’s hard to die of a bruise to the abdomen. It’s a lot easier to bleed out from a lacerated spleen. A bruise to the heart, however, involves mechanisms that a bruise to the heart does not.

Mr McCall rises to the bait as follows: :There is no such thing as hydrostatic shock from a pistol bullet. A .45 ACP  has :about the same kinetic energy as a fastball (run the numbers yourself), which :rarely kill batters, even when hitting one in the head. Except for the brain :and the liver, human tissue is very flexible material, and its being stretched :and released causes no more damage than a minor bruise. And if a bullet was the size of a _base_ball so that the impact was spread over that large an area you would be precisely correct. However, consider that one of the factors that keeps us from making lighter, less bulky body armor is that the padding and spreading of the bullet impact is essential.  It's not that a thinner vest cannot stop a bullet.  It can.  However, if the vest is too thin, you have to start worrying about blunt force trauma to internal organs from the bullet impact, which has the possibility of causing lethal trauma even without penetration. Fred, you are correct insofar as no thin material can reliably stop a bullet of any sort. (Hmm, maybe really hard steel, but that stuff makes crummy shirts), and so when the vest material flexes, some energy transfer is possible. In fact, even the ceramic plates SWAT teams use for center-chest protection can, when hit by a bullet of the .308 Winchester class, transmit enough blunt trauma force to put the heart into lethal fibrillation. (Supposedly some prizefighters have died from this, though I have trouble believing it.) But since pistol bullets inflict injury not by energy transfer, but by physical penetration and direct (crushing) destruction of tissue, the comparison with a _base_ball holds all the water it needs for this discussion. It’s hard to die of a bruise to the abdomen. It’s a lot easier to bleed out from a lacerated spleen. Lensman Hey, Mr. Taliban, tally me munitions. Here they come, and they gonna go boom Perhaps, but would a deep-penetrating bullet like the 147-grain JHPs the FBI went to have caused the shooters in the Miami shootout of 1986 to stop in the first rounds, before they managed to kill two FBI agents and wound several others?  I'm not entirely convinced about this, and the FBI also, in my opinion, might have made a mistake by re-fighting the last gunfight. On the other hand, I've heard about an interesting round from a company called Triton, which produces the Quik-Shok round - designed by Tom Burczynski, who also designed the Federal Hydra-Shok.  The Quik-Shok is a hollow-point/frangible hybrid fired at high velocity (+P velocities), and will fragment inside the target, creating three crush cavities.