I gave this a lot of speculation myself when I was planning my spring (black) bear hunt last year. In the end I didn't take my Marlin 1895 because it's just too much gun for blackies, has problems with trajectory over 250 yards and I couldn't maintain acceptable offhand shooting accuracy due to its recoil profile. (It kicks like being hit by Fred Sanford's 2x4 that he keeps behind the door soaking in a can of motor oil.) From what I've read it might have difficulties in the immediate lethality department if a person was not able to hit a big animal in exactly the right spot. But it would be probably pretty good for close range defense if a person was fishing in bear country. All this, except my exerience trying to overcome the trajectory and recoil problems, is speculation...sorry.
You might want to send a PM to Wildalaska, one of the forum members who manages a gun store in Alaska and who sells a lot of guns to bear hunters. He asserts a number of years experience listening to gun complaints from real bear hunters, knowing which guns they complain the least about.
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In a few years when the dust finally clears and people start counting their change there is a pretty good chance that President Obama may become known as The Great
Absquatulator. You heard it first here on TFL.