You know, I see the recomended depth of penetration for almost all the rounds is getting very close to the same. You really have to make a .357 Magnum open like a parachute to get it slowed down that fast, or, start with alot less velocity.
Also, seeing some of the bigger guys on the street that may be a potential threat, I'm not sure the 12-14" penetration is always going to get to the vital organs, particularly if it has to go through a massive bicep before it gets into the torso. Or, 14 inches of belly fat.
I'm beginning to think that those "optimal" penetration depths are designed more out of liability than real world desired performance. I may be wrong, but, I'm getting a little curious.
I personally have never heard of a round penetrating a bad guy and seriously injuring, or killing, a non combatant. Missed rounds are alot more dangerous than overpenatrating rounds. I'm sure its happened, but, if anybody knows of real cases, I would be interested.
When I carry a .357 Magnum, I carry Remington 158 GR HP. Been around a long time. Good street creds. Doesn't beat the gun to death, hits to point of aim. I think the 145 Silvertip is another dandy round.
For example, the Speer Gold Dot short barrel .357 Magnum sends a 135 GR bullet out at a blistering 990 fps. Really? They actually call that a .357 Magnum? I'm sure its a decent enough round, but, thats .38 Special (barely) +P territory.
I'm sure the FBI has some great ideas, not sure if there is not another motive to thier specs though.