You’re just going to piss off a grizzly if you start shooting it with a 30-30 in my opinion.
Subject to debate. A lot of griz and moose have died from the lowly 30-30.
My walk-about is a '94. In brown bear country. They be bigger than griz. I haven't ever had to shoot a a griz or brown (with anything) , but it's done fine on on couple blacks (actually it was the 336, but still...). ..
30-30 has greater muzzle energy than a .44 Mag handgun, and is easier to shoot accurately, but a lot of people believe a .44 is the carry gun for bear. Could be, if it isn't leaning against a tree a few yards off, as a rifle might be. I'll stick with the '94.
My first moose was taken with a 336 at about 50 yards, 170 gr r.n. through both lungs and out...
Best defense against a Grizzly is a climbable tree or a slow companion. I understand that unlike our black bears that Grizzlies don't climb . Git high and shoot him out from under the tree with whatever you have .
Don't believe everything you read.
There is a local up here who had a sow brown bear (griz's bigger brother) with cubs come up the tree at his black bear bait site. About 16' IIRC. The rifle muzzle was between his feet and inches from the bear's head when he touched her off. I guess she just jumped?
. Black bear season was open, brown bear season not... and of course the cubs...so it was investigated.
Somewhere in the archives there is an account.
As WCH indicated - a griz/brown can go from 0 to 30 in 3 jumps - maybe 16 feet?
There are times a tree will work, depending mostly on the bear's distance and behavior, mostly, but many more when it won't. Like when there isn't a tree within miles... Even if one reaches the tree first and the bear stays on the ground, 10' up is as low as you better be - and that takes time, especially carrying a rifle up with you. If you do.
I also took my first deer with the '94, in 1966. Nothing since. I do have 2/ 1/2 boxes of FTX left to try out. They seem more accurate than the 150's and 170 C&C I have. Interestingly, they (160's ) print just over 2 inches higher than the 150's. If I try them on game at all, it will probably be caribou, out to 200 yards. I carry 170's for walk about. Or maybe I'll use the 150's on the caribou, if I get the chance.
