I carry a .45-70 rifle with me when I’m up north. The high powered rounds I have for bears will also fell an elephant. (In theory. I really don’t want to find out.)

I haven’t heard of .500 blackout before, and google gives conflicting info on whether it’s “necked down .338 lapua magnum” or “like .510 whisper”

polar bears have historically been felled with “panicked shooting with ar-15”, and the “standard recommendation” seems to be “magnum rifle round”