I've never shot a bear, but I did poleaxe a 1200 lb cow with a warmly loaded .45 Colt. My neighbor asked me to put down one of his cows that had a distended bowel, as all he had was a .22 rifle and he didn't want it to suffer. I just happened to be wearing a S&W 25-5 at the time, loaded with home-cast 270 gr RCBS SWC's over a fairly stout charge of Unique. Old Elmer was right, a .45 will go through the frontal plate on a cow, traverse the skull and go on back into the neck. In his autobiography he tells of having to rescue the East Helena butcher who had been treed by a bull. Elmer rode up on his horse and shot the bull in the forehead with his Colt SAA .45 as it charged him, dropping the bull right on his nose. In my case I felt bad for the cow, but at least she never knew what hit her.