Dear Charles, If you can carry it a thirty caliber (or bigger) rifle firing a 220 gr. (or heavier) bullet would be a much better choice. If you are restricted to handguns there's no question the .44 Magnum should be your choice. Chances are if a bear charges you'll probably only have time to get one well placed shot off. You'd better have a cartridge that's capable of doing something with that one shot. Stay safe, Gary
What I want most from the government is to be left alone. GWT
If it has to be a handgun go with the .44 and heavy 300-grain Federal Castcore or one of the other heavy hardcast lead bullets like the Garrett loads.
I have never been attacked by a bear, but I have met one pretty close. There was a time I had reasonable faith in a .44 Ruger Redhawk and huge bullets "for bear", but having read some specific case histories I would no longer feel quite so confident. I would recommend that you study up on bear anatomy, and how this translates into 3-D when they are running fast from the front. Even heavy pistol pistol bullets will likely deflect on the skull - even if you can hit it. Most bear attacks are generally recounted as fast and furious, from very close. In other words - about a second and a half, maybe two seconds, notice.
Everything I have read about black bear says they will turn even if they are wounded. They can climb trees very fast, and very well.
Grizzlies can, even if the heart is destroyed, still tear you up for quite a time - though that doesn't mean to say a minor hit has "never" turned a grizzly too, just that I would count on the opposite. I have read conflicting things about grizzlies and climbing trees; some say they "can't" some say "can". Whatever the case, on their hind legs they can reach very high off the ground. Something to keep in mind.
Of course never attempt to outrun either. I do know a lady who, after a surprize encounter with a bear, managed to make it to her truck cab with a pretty slim margin. She said it was "pretty close", despite the fact that the bear was quite a distance away at the "start". Bears can sprint - very fast.
But forget the 10mm. Better, as has been suggested already, is a rifle. My own choice would probably be a 12-gauge shotgun loaded with Brenneke slugs. Probably a double; automatic ejectors, and double triggers, 18-20" barrels, with a buttstock-band type shell carrier with extras. That - or a pump.
Brown bear or Black Bear country? Brown Bear country would require the 44 mag minimum in my opinion. You may check out the 480 Ruger or 475 Linebaugh. A mad grizzley can take a ton on energy to get down. The 10mm would kill one, but only after it ate you!
Depends on the bear. There is literally a huge difference between a black bear and a brown/griz. If the biggest critter you have to worry about is a black bear, I'd say 10mm is acceptable (if not great) with full-power heavy loads. Anything bigger and nothing less than .44 Magnum makes any sense.
If you are going for a 10mm, stick to Cor-Bon hunting ammo or load your own hot loads.
I took a course the US Geological Survey offers to its field personnel working in primitive areas where there are large predators--most of my classmates were headed to Alaska. The bulk of the course was concerned with defense from brown bears. To cut to the chase, training was based on documented encounters with bears, and ballistics. We were all trained with .44 mag, 12 ga. slugs, and rifles, with the idea that we could make an informed choice about the weapon we would individually carry. The .44 mag was considered ballistically marginal, hard to put on moving target, but better than nothing--the chief benefit being ease of carry. While the heavy rifles clearly have more 1 shot stopping power, most of the personnel were not marksman. And, a person is likely only going to get one shot with a bolt-action, because surprise encounters usually occur within 25 yds. Most of my class opted for a defender-length 12 ga. with slugs. Almost everyone could get off multiple shots in the 3 second closure time from 25 yds. Plus everyone could get at least one shot in the target. Granted, this is a different gun usership than the readers of this forum, but it is another perspective on a bear defense weapon.
Had this talk with a friend of mine who used to guide in the great north, and had messed with his share of griz and brown, he said 12 guage w/ slugs. But, and these are his exact words, if you must carry a .44 magnum pistol make sure you remove the front site first...so that when the bear takes it from you, and jams it up your &$$, it won't hurt as bad. I still laugh at that one.
Optimism? You are confident about making all 6 from a 44 or 20 from a 10?
When I worked in Alaska (SE portion near BC), revolvers in stainless or hardchromed were preferred in a variety of calibers over semi-automatics. That was because of the constant summer rains, humidity, and general dirty conditions. It was thought that a revolver would be most reliable. I never heard of anyone making all six shots that wasn't in a tree stand, safe, or actually being mauled at the time of the shooting (all contact or nearly contact shots). People tend to miss a lot when being charged. People also tend to lose badly if they surprise a bear napping. The guns usually are not worn in an easily accessible manner, the bear gets startled, and gets mad at you.
I really suggest reading the entire series of "When Bears Attack" books. I have no idea of how many they are up to now. In short, 95% of bear attacks tend to be brought on by humans operating in manners that would be unsafe given the ways that bears live. For example, it is a dumb idea to carry 40 lbs of salmon on your back from the water front to your cabin, two miles in the tree line, at night. Do not try to get a picture of your buddy standing next to a bear sitting on the stream bank while the bear is waiting for a salmon to come by. One recurring theme of the books is that most of the victims of bear attacks is their initial surprise of the attack (of those that lived to talk about it). If surprise is not on your side, it is a bad thing for you.