I have to agree that it is the cartrige and shot placement that play a larger role than the caliber. I have shot a doe three times through both lungs with a 300 win and she still ran at least 100 yards. Why? Because at the time I was young and thought hey, a bigger gun means they'll go down faster but I used too much and the rounds went through before they ever really expanded. On the other hand I shot a 450 pound black bear with my .270 using winchester cxp2's and he didn't even take a step. I had the proper cartridge and hit him in exactly the correct location and he was dead before he hit the ground. I would feel completely confident in my .270 hunting elk or other large game. I don't know too many animals that would live too long with a 2" hole ripped through their hearts.