Man, lots of guys shooting little blackies with guns probably better suited to charging coastal brown bears!
Anyways, after shooting, and seeing shot, dozens of black bears, including many with medium magnums like 300 win, 338 win and .375 H&H, my personal favorite is the .270 win with standard cup and core 130's - 150's. Absolutely flattens them on the spot far more reliably than much more heavyweight cartridges.
Loadings delivering 4 000 ft/lbs of energy with controlled expansion bullets are just too much of a good thing for basically people-sized thin skinned game, and the vast majority of the energy from those loades simply blows on through the other side of the animal and does nothing at all...
A black bear is only 12" - 18" across the chest, depending on that animal's size...if your loading has not dumped most of it's energy BEFORE reaching the 18" mark, everything after that is just for internet bragging rights...