Interesting read, interesting responses to a valid question.
After working and hunting in the logging woods in BC for years, having a bear encounter about weekly, then living here in central Orygun for many more years, hunting and out falling/cutting wood, I've had more bear experiences than I can count.
This old boy was cruising the log landing for a few days...
This one ended up in our back yard at our company house....
One morning I found my 3 year old son out back sitting with a yearling cub, feeding him an orange.

Both sitting peacefully sharing the orange......I looked out the window and f'in totally freaked out! Coaxed son inside, the bear cub stood on his hind legs looking through the mud room glass door window before he got bored and wandered off back into the bush.
In all my bear encounters, I've never fired a shot, never really felt in danger, but always had a rifle or my Smith M29 Classic Hunter loaded with my hard cast Keith 245gr SWC's on my hip. When elk or deer hunting, I've encountered them (and cougars) on many occasions, but again, have never fired a shot.
We don't have to fear the bears, just understand them and give them the respect they deserve. Just about any firearm intended for big game would be enough, even that .243 with a good bullet, but in reality, having to shoot a black bear in self defense is a stretch in my experience. Not saying it couldn't happen, but having to actually shoot one would be rare. JME