This always brings out lively debate. I don't have any experience with Brown bears, but I have extensive experience with black bears, and even been in two fights at bad breath range, while armed with a handgun.
When the time comes, the best you can hope for is 1-3 shots that really need to be accurate. If you get more, then great for you.
Cartridge and handgun weight needs to be balanced and determined by your ability to deliver fast, precise shots.
Everyone is in search of the ultimate lightweight powerhouse for comfort of carry. Might I remind you: A defensive gun must first be COMFORTING, comfort is very distant second.
If you have to carry a heavier gun, keep perspective. Handgun weight can almost always be offset by high quality gunleather.
Look to the gun for the comforting part; and look to the gunleather for the comfort part. But don't get the wrong gun to save a few ounces.
You know, America is the only place on earth that would think of carrying a handgun for defense against a brown bear. If you suggested a handgun for defense against lion in Africa, you would be called a lunatic and quietly lead away from the savannah. A brown bear could floss it's teeth with a lion, but we Americans think a handgun is sufficient...or at least we delude ourselves into such thoughts so we're not inconvenienced with a proper rifle. A PH I once met was mauled by a brown bear, after it had soaked up 4 rounds of .375 H&H and 3 rounds of .338 WinMag from both hunters, yet we still have those who go into brown bear country armed only with a handgun.
