I've noticed numerous reports of hunters running into grizzly bears in Montana. I can recall just a few years ago, an upland bird hunter with a twenty gauge stopped a charge from something like twenty feet.
If I'm not mistaken, the Montana wildlife folks document dozens of grizzly charges at humans each year with all the possible outcomes. Seems like each year bears are killed in self defense, but there're also maulings of hikers and hunter, and an occasional death. I have no idea what that moment would feel like, but even if it's just to make noise, I suppose I'd use whatever was on hand.
