Thanks for the replies. My reason for keeping a rifle with me is much more about survival situations that may require food gathering, less about problem bears. I appreciate all the advice though.
The black bears in my area have a reputation as camp robbers, not attackers. Even though the possibility exists of a predatory black bear stalking me, I'm not very concerned about that. I've spent thirty years camping, canoeing and hiking in the bush, mostly with no firearm, and have had no problems so far. I don't believe that black bears in a "bad mood" will attack people, unlike grizzlies. Another factor is that nearly all the bears I have heard of that have actually preyed on people were the 150 lb two-year-olds that were recently kicked off the teat to fend for themselves. Not very big adversaries, but not something I'd want to face with only a knife. So, my intention is to pack mostly .38 special lead round nose loads for food gathering, ( grouse, rabbits and such) and just keep a magazine full of heavy loads for "contingencies". I probably should have asked what works best for deer, and just kept quiet about the "bear" possibilities, but I suppose even using a .357 carbine on deer is somewhat controversial. Small ammo manufacturers like B-bore are not generally available in Canada. Of the big companies, is there a load by Fed/Win/Rem/Hornady that you can recommend?