This is more evidence that arguing caliber isn’t helpful. How well can you aim at a charging Griz? Hit high center until weapon is empty or griz stops.
Not well, I'm guessing. And you won't have much time either. The poor old guy in the article only had time to get off one shot.
I've never seen a bear attack in real life, but I was looking at some on YouTube a couple of weeks ago, and the videos I saw show they don't necessarily charge at you in a straight line (which, of course, would make for an easier shot if they did charge straight at you), but seemed to prefer to arc in fast like the most extreme curve ball you've ever seen. So they're bouncing violently up and down, arc-ing in, and moving real fast. And your life depends on hitting them. Yikes!
Carry a heavy-caliber sidearm. At least you have a chance.