When hunting Grizzly in the Bella Coola (Hagensborg) area in the late 1990's, I was surprised at how small my 300 win mag felt once I got into the thick bush with little visibility, and when I was within 100 yards of a nice big bear...... yes, I know the 300 mag is plenty of medicine but psychologically I was intimidated when there was nothing between me and the bears.
When doing contracted forestry work in the Sicamous area, and being told that Grizzlies occasionally frequent that area, I packed a Remington marine magnum with a pistol grip (loaded with slugs) in one of those scabbards that you wear like a backpack that goes down the center of your back. Again, with that thick bush, I wasn't 100% confident with that choice neither, but a lot of that work was on my hands and knees so it was convenient.
When hiking for recreation, I have the luxury of holding my firearm in my hands so my choice for that is a Winchester model 92 with a 16" barrel, in 44 magnum. Yes, it is not a Grizzly hunting rifle, but it is 100% reliable, very light, and easy to carry.
In my opinion, any bear encounter that would actually require the use of a firearm, would be at closer than 40 yards, otherwise I would probably have the option of backing away. At that close of range, I am thinking that a heavily constructed bullet out of a 44 magnum would be not a terrible choice. I hope I never have to find out.....