In the real world these kinds of discussions are called fantasy. Nobody has ever done it but everybody knows how.....
And I would say it has been done, but you are correct few if any who posted has actually been threated by the brown bear, none by the black. I doubt few have even hunted either bears or as much as sought to watch them wild.
But there are a few.
Even the advise from those will be looked at with doubt, and thus the search for the magic that would save them.
The bear is not a mystical creature that requires a magic bullet to drain it's life. It is a creature who's lack of respect has turned into a animal so feared that most here believe that a simple sighting puts their life in mortal peril as if bears wake in the morning with some bloodlust to seek out men just to maul and eat them. These fantasies are what drives threads like these.
Yes, man has been mauled and killed but with a bears reason, not the sight or scent, not malice but for instinct to protect and survive.
Those that venture into the bears world should be prepared to meet the wrath of a bear when they venture in with fear and ignorance.
Yet most arm themselves with firearms they can't use with the proficiency. They will fail to really understand the speed and stealth. They will fail to recognize when they are in the wrong place.
How do I know this? Why, I read the posts- the holsters, the slings, the firearms you should have, and how much kinetic energy your ammunition has.
Some sound advice, yes, no, maybe.
No credentials for the opinions with no facts to back them up.
How long does you take to recognize you are in trouble or threat exist?
How fast does a bear with intent move?
Me personally, I am no expert, but I have spent more than my share of time studying, hunting, and watching bears.
My single bad experience with bears end well for me not because the revolver I had was big and the bullet capable, but because the condition was recognized and the gun was in hand.
be safe
Ruggy