They were designed to kill people and people are roughly the size of a deer. Of course it would kill deer. It's about a .308. I've hunted with my WWII manufacture M44 (though I never got to shoot at anything. A few warnings...
1) The safety is a bear (no pun intended). I found the safety so difficult to operate that I worried about spooking the deer when I pulled it off. I wonder how many charging Russians were shot in the back because thier comrade was just too weak/tired/indifferent to turn on the safety.
2) Alot of surplus ammo is available that is not only corrosive, it is silver tip PAINTED, not a hunting round. Make sure you get expandable rounds.
3) The point of balance for shooting with the M44 assumes the bayonet is locked open. This is really handy if the deer is real close 'cause you can just lunge forward and stab them. The big hazzard aside from tripping and impaling yourself or another, is the ribbing you'll take from other hunters in camp.

Paul