Live in Alaska bear country 50+ years. Killed my share of bears including one that broke into my house. Nearly always have the .44 in reach and wouldn’t hesitate to use it on a small to medium black bear. Black bears scare easily and I have a 97% chance of chasing them away by throwing rocks and making noise.
Brown bears on the other hand are scary big (some over 1000 pounds) territorial, and very unpredictable. Short barrel .375 H+H in high risk brown bear country. The only good a handgun will be in a big bear encounter is to use it on yourself as the bear is tearing you apart. Be sure to bring a can of bear spray so you are seasoned properly!
The Alaska department of fish and game has a bear protection course where they have a bear sized target that is attached to a pulley system to make it “run” at you at bear speed. You shoot with a variety ove weapons to see if you can hit the target. The poorest performance by far was with a handgun with less than half the participants in my class were even able to hit the thing. Best was with shotguns. So much depends on experience!
In real life, pistols of a large variety of calibers are 97% effective in defense against bears.