Yeah I think a .44 magnum with the heaviest, hottest loads would be about the best choice for a hiking backup gun.
Of course, most hikers seem to get by by avoiding the bears and giving them a chance to avoid you. I probably wouldn't be field crafty enough to do that unless it was something obvious -- probably be a darwin post about me at some outdoorsman site -- but then I probably wouldn't be going into bear country without being with someone who was.
I think for a light handy rifle, my Enfield No. 5 would be a good choice. Really light and handy, and the recoil for me is nothing compared to its reputation. The .303 isn't a top rifle cartridge, but it has dropped elephants and most North American big game. You can also load it with heavier hard cast rounds.
Now, if you run into a pack of Wolves
I saw a discovery channel piece on the mega fauna 10000 years ago in north america. Bears, lions tigers various gray and dire wolves... Most about 25-50 percent bigger than they are today.
In gun circles you always have the SHTF discussions, or what if you had to hunt T rex... I wondered what would be a good weapon for surviving that. You would have 2000 lb bears, 1000 lb lions and tigers and packs of 150 lb wolves. All hungry and as yet, probably not that afraid of man.
Our ancestors got along by working in groups with spears which get the job done if you have enough of them or the animal knows to fear them and decides to go elsewhere for easier meat.
But being alone in that wilderness with what you could readily carry and perhaps an ammo stash at a home base cave...
What would meet the threat of both a 2000+ lb bear and a pack of wolves?
Charon