I never hunted a Brown. As far as I'm concerned I guess it depends on the distance between the hunter & his quarry. I know
my preference would be as far away as possible from an animal such as that. {being there's always a chance for a serious wound instead of an outright kill.} So having distance between us. I would prefer a caliber that fits the situation and is known for its ability to reach out long distances like those 300/340 Weatherby's can do.
For a close in shot where a wet nose and pair of canine teeth are easily identified coming towards me at a pretty good clip. One of those Big Bore Marlin lever rifles like that 1895 in 45-70 would come in handy. {no doubt its cartridges would be loaded up by me and me alone.
No factory ammo on this hunt.}
Maybe my choice of short range rifle may not stop a really BIG Brown's charge. "But I do know I'm going to change his direction of intent!!"
And that may be all I need to witness at that undesirable e~vent._