I was using a 4 inch barreled revolver-

The important info came from the other posts that responded- Not many thought well of the 357. I don't believe the difference in velocity between a handgun and a rifle is going to significantly increase the killing power.
There are very few people that have to deal with a charging black bear, and a miniscule number that have stopped several charges, so we have to go with what the researchers tell us.
Bear spray is the overwhelming winner when it comes to bear attacks that have been documented, from all the info I can gather.

Royce