My long-ago background was as a bear biologist. I started out working with polar bears, then went on to study grizz and lots of black bears in B.C., the Yukon, the NWT and finally Alaska. As well as time in Churchill, Manitoba ("The Polar Bear Capitol of the World!" or so it says...).
I initially carried a .44 mag S&W sidearm for personal protection
, but with standard factory 240gr loads that proved to be a bust. For rifles, first I carried a .308, and many of the Provincial boys carried 30-06s and even .303s (this was, after all, in Canada!). One, a senior biologist, only carried a 6" bbl'd Ruger revolver in .357 Mag. An optimist I suppose...
(Now, I lug a .454 Casull around, but ONLY if I have to... Lord, talk about recoil!)
Eventually however, in about 1976 I ordered and bought a brand-new semi-custom Weatherby (left-handed) in .340WM. (BTW, that cost me... wayyhhhtttt foritttt.... $472 in Canada! "Please sir, can I have some more?").
An awesome choice to be sure, and ballistically nearly identical to the .338 Lapua. Shot 3 rounds of Norma factory ammo into 3/4" @ 100 yds too! Only had to use it once on a wounded polar bear, which I potted from a nice safe helicopter, but the effects, from about 40 feet above him, were truly amazing: It was pretty much like someone had pulled out all four of his legs at the same time, and he was down.
Then I shot him again, just for security.
(PS: Mesarifle's Rule: NEVER shoot a bear just once!).
Later, when I was dealing with more blacks and the occasional grizz, I switched to a new Marlin 1895, with my own conservative but potent 45-70 handloads: the 350 gr Hornady Flat Point in front of some 3031 for a measured V of 1950 fps @ the muzzle. That ABSOLUTELY took care of over 25 black and one grizz bear, definitively. That was at least 25 yrs ago, and now you can get those LeverEvolution 325gr (@ about 2300 fps! Wow) rounds, or some CorBons or Belt Mountain loads, all of which will ABSOLUTELY stop any bear, and even a Cape Buffalo, in their tracks. Probably even reverse their direction, cleanly skin them out
and tan and then fold the hide, all with one simple trigger pull!
No need to go for big, expensive bear guns with those stainless-steel ported Marlins around (BTW, there was nothing wrong with the Weatherby; it was just too nice looking a fine rifle to be dragging it into and out of trucks and helos! Roy Wby. would have been most upset! Oh, and it does kick like a demented mule without any sort of M-Brake on it! Ouch! And cover your ears as well!).
Jist me two-bitz worth! Happy bear hunting, but always check your "6"! Oh, and don't forget Mesa's bear shootin' rule neither!