> I'll just point out that knives are obviously not very good ranged weapons, due to accuracy, distance, and expendability problems.

Damn straight. You have to get in close, giving your opponent more time to prepare (or run away). Not to mention that it takes some skill or luck to kill someone with a knife. A gun requires a lot less of either.

> it's not like most guns we're talking about here are being shot at enough distance and enough velocity without enough rifling to actually cause the bullet to tumble and explode like would be required in the wound you're describing.

Well, I can not claim to be an expert on ballistics, but I was under the impression that a bullet is quite likely to change direction inside of a body, and that a fragment is quite likely to happen if it hits a bone. Perhaps I am wrong and it is more likely just to bore right through you in a straight line, but I still think I proved my point.