REALLY DEPENDS ON THE RIFLE.
I wouldn't give anyone a 450 or 500 Nitro Express, and say shoot it, unless they had tried something like a .375 H&H First.
I've never shot anything that recoils over 80 ft pounds.
Perfect gun I saw for bears was a .500 A2 Ruger #1. At 7 pounds, it recoiled near 220 ft pounds, with 600 grain bullets, at near 2400 fps. Shoot the bear. If you miss, at least your not awake afterwards...
S