Let me clearly state here that I am no expert on either bears or the 357 round in revolver or rifle form. My intent was to point out some information that I had been exposed to, and let others decide if if applied to their situation.
In the process, I ended up learning something, namely that Buffalo Bore makes some very stout loads for the 357.
I believe there is a significant difference between taking a big game animal that you have stalked and/or is unaware of your presence and stopping a determined charge from a few feet away of an animal that could weigh 400 or 500 pounds.
I don't understand the logic of "Well, I am going to take a bear protection gun, but I won't probably need it, so I'll take something that will maybe work".
Phil Shoemaker, who posts here as 458 Win has written about using the 357 as a bear stopper, but he and his family live with bears on a daily basis and are very familiar with bear behavior. I believe in one of his recent articles, he said that in the 25 years or so that he and his family have been guiding bear hunters and living in bear country, he and his employees have only had to kill one bear in defense of life and property. However, when the rest of us mere mortals encounter a bear, there is going to be a lot more of the pucker factor involved.
Bottom line, if you believe the 357 is an adequate bear stopper, you could be right.

Royce