HuH !!!
First one of the best elk hunters I know packs a Belgium BLR in .308, I have seen him only not fill his tags once in 10 years, and that was after a bad winterkill. Must work for him.
Comment on a .308 and short action, my choice would be the ever unpopular .358, 9x57, 9.3x57 and 375x57 on big critters I subscibe to Elmer Keith theories. None of these would be my first pick for a big brown in a willow thicket.
Somewhere buried in my reloading room I have a study and report done by the U.S. Forest Service on the effective cartridges against bears. It was given to me by a friend who worked as a surveyor in coastal Alaska. Seems the Forest Circus was having problems with brown (grizzly) bears and particularly survey teams. A small problem of multiple engagements with the teams that the human side usually lost. Got to be a civil servants nightmare, liability, insurance, survivors benefits, neglegence, etc. So they proceded to spend our tax dollars to figure out what was effective on stopping a bear. They pretty much went through the gambit of readily available hardware and cartridges, ( there is none more cautious or thorough than a civil servant covering his ???).
The findings were somewhat as expected in some cases, and big suprises on others. The minimum recommended cartridge was a 30-06 with 200gr bullets, big suprise ( to me anyway ) was a 12 guage shotgun with slugs ( buckshot sucked ) and the 3" mags are what they recommended. The other tested guns were 458 winchester, Weatherbies Magnums, 338 mag, 30 Mags, 45-70 and 375 H&H. The Weatherby magnums overpenetrated and were less effective. The 458 didn't do bad but didn't fare as well as I had thought it might. The most effective ( at least in our governments eyes ) was a 375 H&H mag, with 300gr bullets, with the barrel sawed off to 18". Longer barrels than that were deamed to difficult to wield rapidly in thick timber and brush ( seems that is one of the things they really disliked about the Weatherby rifles). Remember this was done for close in encounters of the personal kind. They wanted to stop a charging bear at 10 ft dead.
I believe in all good traditions of our most esteemed civil servents there now is a policy in place ( in Washington ? who knows ), where survey teams have one member of the survey team is issued a sawed of 375 which he cares at all times in bear country. I think there standard rules of engagement are they are to shoot any bears closer than 15 yds. ( I need to find that article cause I want to check that range again as it has been several years ).
If it works for them who am I to second guess my government tax dollars at work.
Comment on 243 against polar bears. Yea I been to Barrow and the locals seem to prefer the 243 for everything. But they do some really stupid things on a regular basis, I wouldn't call heading of across 35+ miles of ice blind drunk in -50 degree weather real smart, yet that was a Darwin award during my time there. They hunt the bears usually with their dogs, and almost always have much greater distance between them and the bear, than a typical encounter with a coastal brown.
Edited: I must be drinkng too much caffiene and reading Kafka