I am a former Alaskan. The .300 Win is perfectly OK. If you are hunting grizzly bear as a non resident you will be hunting with a guide. A competent guide wil be there to back you up and will have a rifle capable of handling a big bear. The .375 might be considered a bit of overkill for sheep but if you are with in 350 yards you are ok on balistics. Take the one you shoot the best.