Let's amend that - anyone hunting in grizz country needs their heads screwed on straight. The bears know what a dinner bell sounds like. Mark had too little gun (I think we can agree that a 10mm Glock is light for stopping a charging grizzly bear), wasn't cautious enough, and trusted his client too much. And while he was a friend, he died because he made a series of poor decisions. One of those was the gun.
If you knew for a fact that you would end up in that situation, you'd want all the gun you could get - likely something in the .458 to .577 range. Since no one knows what the future holds and you have to carry the thing and likely want some reach as well as a stopper, something like a light .375 is a reasonable compromise.
I live in grizzly country and would pick my 06' over a .458 or .577 every day of the week because I can shoot the 06' better and am able to make quicker (and accurate) follow up shots without concern with flinch.
And as far as elk cartridges go, my stepfather shot elk for over 35 years with a .270 before switching to .300 WBY. and continuing on for another 10 years. I witnessed kills between the two and they all died the same...and the first 65 elk were killed with the .270 shooting factory Rem. Bronze points.
I killed my first elk with a 300 savage, followed with .270 and 30.06 for the rest. I may try some trick shooting and switch over to the antique 6.5x55, risking life and limb whilst hunting in big bear country just for the fun of it.
