The reason I say the 357 is up to the task, is only a CNS shot will stop a charging bear, and a heavy hardcast from a .357 will reach the brain or spine just as effectively as a 44, 45, 475 or 500. None of those more powerful handgun rounds placed somewhere are going to stop a bear, they also need to hit the cns.
I would diverge a bit from this idea in that, while one should not and cannot count on peripheral shot stopping, the bigger cartridges leave one with better prospects for frame breaking shots beyond a "vital miss" around the head or neck. I better trust and much prefer the idea of using a 300 hardcast or solid-type bullet moving at least 1000 fps. A 400 in a 480 moving the same would also be useful. If that takes out the spine at any point, or the pelvis, great. If all I get is one leg, that buys some time, however momentary it, perhaps, is. Stopping a bear is the ultimate time stopper. But slowing the process is another way to accomplish that outcome. While I prefer a handy carbine for bear duties when I really don't want to kill one, I think many times the now-mid-level big bore handguns get overlooked for the monster-mags. I have no use for a defensive handgun cartridge that blasts a bullet out with pressures required to move it at 1500 fps, give or take. Stout 44 Mag or 45 Colt loads or 480s seem just about ideal to me.
