I don’t think most handguns would guarantee the grizzly wouldn’t just laugh it off and then maul you.
There are no guarantees in life. All you can do is prepare the best you can.
Grizz? A Ruger Alaskan in 454 casull Or .480 Ruger will kill a grizz. Question is would the mortally wounded grizzly kill you after you shoot?
Hopefully Ill never have to find out.
I have been looking for pistol defense against bears failures.
Have not found any so far, but a dozen cases where pistols worked to stop bear attacks or prevent them.
http://gunwatch.blogspot.com/2016/10/where-are-bear-attack-pistol-failures.html
I am updating the article with several more successful uses of pistols to stop bear attacks. About 20 now.
I suspect a handgun would be more effective than ‘bear spray’.
With the right shot placement a grizzly can be killed with a .22.