Have read many times that the 30/30 was pretty much the standard rifle for Eskimos and some other northern types - who used them on everythi9ng including Griz, Browns, and Polar Bears.
I read a 30's vintage American Rifleman article. The writer had gone to Alaska and brought his 30-06. He went seal hunting with the Eskimos. In this period of American history, the 30-06 was considered, especially with the military staff at American Rifleman, "the round", and about the most powerful round the average guy could afford. A box of rounds for a 375 H&H were probably a weeks pay for most people.
The Eskimos had 30-30's. Why? That is what the Trading Store carried. The Trading Store had also convinced the Eskimos that octagonal barrels “shot harder” than round barrels! (Probably because an octagonal barreled 1894 cost a $1.50 more and made more profit for the store) So the Eskimos were making fun of the wimpy round barreled 30-06.
That is until the author shot through two seals with one 30-06 round. I had the impression that a 30-30 would not do that.
One other thing with the Eskimos, they were meat hunters. Bringing home food was a matter of survival. The modern trend of long range shooting at an animal, just to see if you could hit it, and then loosing it, would scare all the game off. And there was no guarantee Mr Eskimo would find another that day, or week. They were into the sure thing.
I suspect they only took on Grizzly if they had to. Or had a lot of buds as backup. If a bear wounded them, infection would set in, and then they were a burden on the others if they recuperated. Since hospitals and ambulances were not around the corner, they also stood a good chance of not recuperating.
As for me, I would want to take something into Grizzly country that was more powerful than a 30-30.