as said... better than nothing, but, may not be better than pepper spray, or even lesser calibers... I would guess the 45 ACP would be lacking on penitration... & in reality 9mm may actually penitate deeper through tough bear hide, muscle & bone... of course FMJ only on bullet selection...
personally if carrying an auto I already own, I'd choose something else... maybe 10mm, or one of my Automags...
but I'd prefer my 454 Casull Ruger Alaskan