If I was hunting griz/brownies, I would go with my .300

If I was shooting a bear that was charging me, my benelli black eagle with 1 oz. slugs would be my choice. The shock power of the slugs combined with the fact that I could get 8 slugs into the bear before I had to reload would outweigh the 2-3 shots with a .300 . The shock power of a .300 is not as much as a 12 ga. And even though we didn't kill the bear, I have been charged by a sow grizz and she covered the 50 yards that she started away from us in the time it took my dad and me to scramble 7 feet up the tree that was 4 ft to our left. So about 3 seconds. You would barely have time to line up the rifle once let alone more times. A shotgun is more suited to fast aim. I could get three maybe four shots off with my semi auto.