if the grizzly was on standing up growling at me... (300 weatherby mag) would knock him down in his tracks.. but if he was running at me i still would take the 300 weatherby if it was open sites and not scoped...i have a box of weatherby 220 grain round noses and a box of wolf brand buck shot in front of me as i type.. well i have to say i would never change my mind..lol