Another option is the Smith & Wesson Mountain Gun. It is made specifically for backpacking. Every year it is made in a different caliber, either .357mag, .41mag, .44mag or .45 Long Colt. It is only a six (or 7 in the case of the .357) shot revolver, but these calibers are quite stout. It is a half lug, with a smaller outside diameter barrel to cut down the weight. My g/f has the .357 and it is one of the nicest revolvers I have ever shot.