"Good Lord! That must have been a change of underwear experience!"
If you find a grizzly at peace with himself and the world, a marginal shot (say 22 CF) might be OK. But, if he is wounded, agitated, annoyed, angry, horny, aggressive, or otherwise in a bad mood, I think your insurance agent would prefer you to have a large caliber rifle. In my case, we'd see 3-4 grizzlies a summer when working in the back country (where trailcrews work). 99% of the time, they'd sense you and move along � no big deal.
In 1960, following a bad attack (ranger, 12 year old boy and female tourist), I bought a 44 Mag. Ruger and carried it with me. Each Monday, my job was to hike up to Grinnell Glacier (Glacier NP) ahead of the tourists, clear the trail of any fallen rocks and, check the outhouse near the Glacier. I�d descend via another trail and check it out for later work. I was going up toward Piegan Pass when I saw a bear 100 yards or so ahead; I stopped to wait for it to move when it started jogging (not running, but not walking) toward me. I was at the tree line and climbed the nearest tree (probably 9-10 inch diameter at the bottom and 4 inches 15 feet up). Long story short, I shot it as it was standing trying to reach me, climbed down, rolled it down the mountain and covered it with blowdown. I never reported it as carrying a firearm in a park was a felony as was killing any animal (2 felony convictions at age 18 would have probably jeopardized my employment outlook). Two other bears were killed that summer (one legal, one not).
In 1961, we were working at Lake Isabel and knocked off early to go fishing. I moved about 100 yards from he other guys and suddenly was overcome by a rotten smell (grizzlies do not bathe, use deodorant, nor brush their teeth; they can really smell foul!). I dropped my fish into the lake and walked out to waist deep water. I never actually saw the bear, but we found paw prints in the mud on the other side of a large brushy area � about 20 feet from where I was fishing.
In 1960, I was actually too busy to be scared (getting up the tree, shooting the bear, rolling it down the mountain and hightailing it back to my pick-up point about 6 miles away by 4PM). In 1961, I really did get scared, standing waist deep in very cold water just knowing the bear was going to get me.
I understand from some books that seeing a grizzly in the wild is a real privilege, and it can be. But, when you are alone, it�s a different story. I understand that the National Park Service no longer permits employees to work alone in grizzly country.
