Killed a lot of grizzlies have you emerson?
I’m not worried about an Amax holding together on a big bear at close range. When I was specifically hunting grizzlies for myself or with buddies I generally carried my 300 Ultra or 7wsm stuffed with TSX’s. Also used to carry a 45/70 with Buffalo Bore rounds, but that was more for having to go dig one out of the alders.
I’ve never really worried about bears since I work in the bush, and spent years working alone km’s from anywhere with nothing more than a can of salad seasoning on my hip.
Hoyt really nailed it in one of the bear threads about reading bear body language and being smart about where you are. Worrying about a bear attack that for the VAST majority of hunters will never occur isn’t really worth the thought. Not many people are going to be able to react quickly enough or smoothly enough to use a rifle adequately in a charge situation, and a lot of internet cowboys have some pretty grand fantasies of how they will perform in that situation using their big magnum.
That said, if it brings you peace of mind to carry a 458 Loudenboomer just in case you run into a bear, then by all means carry what you like. For me though, I worry more about rifle familiarity, fit, function, and point-ability over everything else.