I could picture a dinky .22 rimfire just pissing off the bear, if you didn’t hit it just right. Given my druthers, I’d be in a different state entirely, even with my 12 gauge magnum load.
Slugs are a great round. But large animals such a large the large bears have thick hair and skin which slugs have trouble penetrating to reach vital organs for a kill but would tend to seriously discourage them.