When hiking in bear country I carry a Mossburg 500 with an 18 1/4 barrel and shortened stock. 00 buck and slugs alternated. Recommended by an Alaskan Game Warden. carried within easy reach on a larger pack, secure with velcro straps.

But wouldn't a pistol be better if you were 'surprised' by a bear??? With the laws about short barreled rifles we have, almost anything you can find would seem to be way too long for close in work...
Not that I would LIKE to ever get close in to a bear, but given how fast they are, and the fact that you may stumble on to one by accident, it would seem that something that you could use while on the ground or in a tree would be prudent...

I'm not a bear hunter but I sure would like a skin with skull in front of a fire place. If it were me a 41 mag. is the smallest I would consider. A 44 mag. would be even better. Double action with a grip that fits your hand well. I would want a lanyard attached to the butt long enough to hang around my neck and fit in the holster. You know Tucco style from The Good,theBad and the Ugly. Loaded with Garrett Hammerheads for deep penetration. This is your life were talking about.

-And the bears too.