They really aren't reliable enough. I see a few guys here and there who are carrying a 10mm Glock, and they're always pretty young guys. (under 30). Additionally, 10mm, in most factory loads, just doesn't have the knock down power that a 44 magnum has. Then there is that thing about being shooting cast lead in a Glock or something. You really have to reload 10mm to wring all the potential out of it. Then there is the issue that, if I'm basically under a bear, and I press the Glock muzzle into the bear's chest, it will come out of battery and not fire. So, for most folks up here, a revolver is the bear gun of choice. (44 magnum is considered the smallest, minimum, caliber.)