re: You will pardon my skepticism
Easy to say sitting in front of a monitor, and not trying to aim a gun at a half-ton of approaching carnivore. ;)
There's a big difference between hitting a bear and hitting his tiny little brain. And good luck getting a heart shot in if he's galloping straight towards you.
Best way to keep out of a grizzly's way is to KEEP OUT OF HIS WAY. I don't trot around in the woods in bear territory. Don't swim in the Pacific Ocean, either. Me and the Great Whites have a deal--I stay out of their yard and they stay out of mine.
Sympathies to those who actually live in grizzly country and don't have a lot of choice. I recommend RPGs.