Will you be hunting with a guide? If so, ask his recommendation. About a yr or 2 ago a thread like this came up about a coming big bear hunt. The OP in that one has a 7mmWSM or maybe it was a 270WSM, I don't remember which. Anyway, I recommended a .338 or a .358, and was promptly chastised by a couple of Canadians for my suggestion. They insisted the WSM (whichever one it was) was plenty of gun. But, again, I would defer to the guides' recommendation. I have a client that went on a guided sheep hunt on Kodiak Island. His guide recommended a .338 or more, because of the presents of the big bears. If you're paying a guide, that's part of what you're paying for, his expertise and recommendations, not just someone to 'show you around' and hopefully lead you to your quarry. Take what you are comfortable with, what your guide recommends and, a back-up gun ain't a bad idea either!