My experience differs from this a little. A bear under 300 lbs is still tougher then a whitetail, but agree 100% they are effectively taken with deer rifles all the time.Black Bear are not particularly difficult to kill. Any sensible deer cartridge with a decent bullet will do. They can get heavier than a deer. For close range work, a 30-30 class cartridge comes to mind, in a shot gun slugs not buckshot 20 ga. and up, and 10mm and up in pistols, is where I land.
Largest Black Bear I have seen killed dropped to a 180gr JHP out of a 10mm at about 80 yards. About a 475 pound animal, most are much smaller, a few can be larger. I generally carry a 270 Win or 280 or 7mm-08 for them with 130-160 grain bullets as shots can be long where I hunt, otherwise a 30-30 Win or 35 REM would suffice.
I’d have zero issue with a 20 or 12 gauge with slugs for hive defense as that would seem to be very close work.
Stopping a big 500-650lbs monster like we have in the coast of BC and occasionally on my farm in Quebec is a very different animal. I don’t want to “hunt” them with much under a 30-06 and prefer a 338, 35 or 375 to “stop” them.
At close range a 12g pump with a round of 000 in the chamber and a bunch of slugs in the tube is my first choice.