"Sorry - speed in and of itself does not kill. The only thing that kills is cessation of oxygen flow to the brain via CNS shutdown through whatever means. With bullets that is accomplished by tissue damage rendering said systems non-functioning."

I was actually talking about a fast bullet will more than likely penetrate steel better than a slow, heavy bullet. I was not talking about tissue damage in game animals.

It has been my experience that high velocity bullets penetrate deeper into steel than the slower bullets.

But, since you mentioned it, an expanding, fast bullet of adequate weight will do a good job of tissue destruction, too.