I have killed a mule deer with a 357 magnum. The shot hit the heart and 1 lung then stopped on a rib on the other side, the round was a 180 grain cast lead bullet from buffalo bore. The deer dropped when hit but got back up and ran 30 feet then dropped again.
as my name implys I love the 357 caliber. I have taken several deer a 357 maximum Dan Wesson revolver.
I recomend using heavier bullets 158+ grain but that is just my recommendation.