In grizzly territory a handgun is only slightly better than nothing. MAYBE, if you get a lot of rounds into the beast, will you drop the BP enough to get it down, or get a couple of shots into the brain. MAYBE
Big game requires big guns, as a rule. Of the guns I actually own, I’d prefer my plain old shotgun with magnum slugs to deal with a charging grizzly. When they get their dander up, you basically have to tear their hearts or brains apart to get them down, so I’ve heard.
Handguns are very effective against bear attacks don’t believe the anti firearm anti hunting drivel.
Please read the below Link about bear defense.
http://gunwatch.blogspot.com/2018/02/defense-against-bears-with-pistols-97_25.html