the 10MM is no 44 mag which I would recommend for your purpose if bears are involved. The 10MM is approximately the equivalent of the 357 Magnum and should be good enough for cougars and 2 legged varmints along with the 357 magnum for this purpose..

I've never been face to face with a charging bear, however I would imagine I would want the biggest and baddest weapon in the world in that situation. A shoulder fired rocket propelled grenade would be my first choice.

However we would temper that equation by saying "What is the biggest, baddest weapon that I would be willing to tote around in the woods?" For that I think I would go with the 10mm Glock. A round from Double Tap will generate 700 ft/lbs of energy. The small Glock (Model 29) holds 10 +1 rounds. It is very light, and relatively easy to shoot (relative to a .44 magnum). The full sized Glock (I believe) holds 13 +1.

I don't think I would go hunting bear with a 10mm, but I think it would be my first choice for a defensive round against thugs dressed up as bears.

men are by far the greater threat, both in severity and frequency of occurance. I either just carry the same pocket 9mm i always carry, or I step all the way up to a 308 autorifle. if you are attacked by a big animal, no pistol amounts to much. even with the rifle, only brain or spine hits are likely to stop a charge. 100 lb deer often run 50 ft or more after being heart shot with 3006 softpoint rds, so why would you expect any sort of hit to the body to stop a bear, hmm? wishful thinking does nobody any good, and could easilly get you hurt.

Where you could stumble upon a large, angry bear, I'd carry a rifle like the .308 and an SA revolver in .41 magnum though .44 mag and .454 are also good. The 10mm probably does not have quite the power.

The Glock 20 can be modified for not too much over a hundred dollars, by adding an aftermarket barrel with conventional rifling and 22 lb. recoil spring. This makes it able to shoot 200 grain hardcast lead bullets, loaded very hot, and gets the 10mm solidly into .41 magnum territory, just below the .44 magnum. If this round is manageable, which I believe it is, with practice, I wouldn't feel too bad about it as the last line of defense.

A large, hungry brown bear would probably still win in most circumstances, but if you managed to climb a tree fast enough to turn and start emptying the magazine into the bear as he climbed after you, you might turn him around. The 10mm is definitely a compromise between what you need, and what you are willing to carry, but I think it is a reasonable one.