You should have been more specific,and mentioned it was a 45 caliber Long Colt round you were talking about,not a 45ACP. Don't get me wrong,I DEARLY love my custom Combat Commander in 45 ACP,but it ain't a bear gun. Not even with my "Banzi!" hand loads.
@sneakypete Kinda makes no difference... If I am pulling a pistol it's because the 45/70 is empty already, thrown aside, and/or the problem is close in and personal... And I am having a really bad day, no matter what at that point. What works best there (IMHO) is fat lead and as many as I can put into it as possible.
Mostly that would argue toward ACP, but I have already told you my preference toward a Colt. Familiarity means I can mechanically, confidently, put all six where they go... Which is more likely than any extra I might get out of an ACP. The 1911 is still awkward to me. But that's just me. Many, many years with a Colt. It's a piece of me.
Truth to tell,neither is a 45 LC round,but it damn sure comes a lot closer with the right load and bullet. When it comes to brown bears,I much prefer something like an A1E Skyraider. There is no such thing as "too much brown bear gun".
Nothing in a hand gun is enough. Any hand gun is a last act of defiance. Moose or griz, particularly. Truth be known, I would rather have a 12ga. full of double ought or slugs, even better... But I settle for a lever gun for the extra distance and versatility in the bush. The handgun is the absolute last gasp. If I am past that, down to knife and tommy, I am not likely to walk off at the end. Just a bare fact.
A dangerous man ain't no different. Distance and cover are way better than up close. I reckon I'd prefer 500 yds to 50 yds, any day. It's how I know best to do.