It's all about blood vessels, veins, and arteries. The more stuff you cut from point a to point b, the quicker they will die.

I don't care one bit about an exit hole. I want to cut the most "soft" tissue as possible, and they won't go far regardless of what the bloodtrail looks like. I shoot a 1-3/4" cut mechanical for that reason - tons of damage - they are dead quick!