I considered the 9mm but dismissed it for its higher velocity and what I stated about not wanting the slug to exit a body. I might feel bad if it went through a wall and hurt a neighbor or...left a hole in my own wall.
Im going to try and find a link I read a while back. It was basically a book a guy wrote. This guy was a coroner, and he said that about 80% of the time, when the bullet went through the victim/suspect, it was found caught in the shirt or whatever clothing they were wearing. Meaning it loses almost all of its velocity by the time it makes it through.
Now Im not saying you should just shoot at someone with a .357 MAG when there are a bunch of pregnant ladies behind him, but you get the idea.