I started off with a 243. I believe if you put a big game 6mm bullet through the ribcage that deer will die before it runs a 1/4 mile. The problem is some of them do and some of the blood trails will be dripping spots far apart. I killed 30 something deer with.mine and only lost 1 I thought I hit. Never found blood and he was a brute. I moved on to bigger bullets with no regrets. I wouldn't use one for deer hunting unless it was my only option. I realize other people feel otherwise. I would rather have a millisecond of recoil than spend a long time tracking and dragging.
