Shooting into shoulder bones is a poor shot in my opinion.
A neck shot is good,or just behind the elbow if side or quartering away..
that is thinking a bit like a hunter explaining why you shot a leaving bear might land you in hot water.
if your defending yourself chances are good the bear is coming at you the question is on 2 legs or 4 , given the descriptions of successful bear defense with a handgun , it sounds like often on 2 and the shots were fired relatively close and into the lungs through the ribs
it could also be on 4 and would make a harder shot , head , neck and back if head is down.
if a shotgun , slugs work well on black bears 1oz lead maybe a griz is different but I doubt it , they are not long range tools but 1 oz rifled slugs are 3000fpe in close boring a .72 inch entry and can expand to more , and have good penetration close .
I think there is a saying if you knew you were going into a gun fight you wouldn't go , if you did you would bring backup and rifles.
if you knew you were going to get attacked by a bear you would bring backup and rifles or shotguns with slugs.
but you are there to fish or hike or hunt something other than bear.
bears spray good and hopefully you don't even need that if you do you have it and use it and likely that is enough.
handgun not bad backup to bear spray much easier to carry than a long gun
another saying , your handgun is a tool to fight your way to your rifle well if you happen to have a long gun but it is strapped to your pack or you set it down to cook , setup a tent or some other task.