I've used a .270 very successfully on deer, ELK, Alaskan Moose, Kudu, Zebra, Sable, Caribou, Pronghorns, Dall Sheep, and other animals.

I'll be hunting in South Africa this summer and may very well be using a .270 to shoot an 1,800 pound Eland. It'll work fine for elk if you use quality bullets that are heavy for caliber, like 140s and 150s; pick your shots wisely and know when to pass on a shot.