My Grandfather killed a number of them in the 30s and 40s and swore by the 30-06 with 180s. I know a gent in Canada that like the 303 with 180s iirc and he had bagged several as well.
Personally? I’d be confident and comfortable with a 7-08 and 160s as a good solid minimum. My personal ideal choice would be my 308 with 180s @2700fps. I’d have zero hesitation with that combo for anything in N America
You don’t need a cannon...you need penetration and shot placement as with any game animal. You will not impress a 1000lb bear with any amount of ft/lbs. I base this off of the opinions of the masters...like Phil above and my experience on heavy game though no brown bears
