I carry a 45 Ruger Bisley SA with hot loads in Bear country. I have not shot any bear with it though. I do recall reading about a park ranger who carried a hot loaded 45 SA for years and found it adequate for shooting scores of black bear.
I sleep with the Ruger close at hand as it is more accessible and handy than a rifle in close quarters and should serve well for a non adrenalized hungry bear who is tent shopping for food.

In the open with a pissed off bear that 45 Ruger is not enough gun and a rifle is needed.

IMHO--different circumstances, different weaponry for big bear encounters. For smaller black bears the handgun alone may be adequate.