Just overpower them:
For big bears, most of the tests I've seen online recommend .338 and up with heaviest bullets possible. Shotguns are next, then pistols. All the shotgun slugs they tested broke up too easily against bone, thus not penetrating deeply enough. So if you can't get a rifle, hardest shotgun slugs you can get... Brenneke Black Magics etc., assuming they make those in 20g.
Good luck, I read a lot of stories where the hunter never got off a shot and was mauled by the time his friends were able to drive the bear off. I also loved the park rangers story of when they had to go retrieve the body of that failed actor grizzly guy who lived with the bears and was killed. People get in trouble if they shoot a bear unless it's basically mauling them, but the ranger admitted that he and the other officers were opening up a hailstorm of bullets on every bear that looked at them funny while they were getting the body 'cause they were all scared stiff.
For big bears, most of the tests I've seen online recommend .338 and up with heaviest bullets possible. Shotguns are next, then pistols. All the shotgun slugs they tested broke up too easily against bone, thus not penetrating deeply enough. So if you can't get a rifle, hardest shotgun slugs you can get... Brenneke Black Magics etc., assuming they make those in 20g.
Good luck, I read a lot of stories where the hunter never got off a shot and was mauled by the time his friends were able to drive the bear off. I also loved the park rangers story of when they had to go retrieve the body of that failed actor grizzly guy who lived with the bears and was killed. People get in trouble if they shoot a bear unless it's basically mauling them, but the ranger admitted that he and the other officers were opening up a hailstorm of bullets on every bear that looked at them funny while they were getting the body 'cause they were all scared stiff.


















































