It would be useless against a bear anyway, well it would probably afford protection against a cub but not mama or papa bear, all of those overlapping plates would do nothing but allow them to latch on with their 3-inch-long claws then just rip the thing apart. The best protection against a large aggressive bear is to not be there in the first place. Baring that the next best thing is a 454 Casual, if possible, try to aim the shot up through the lower jaw into the brain stem. A heart shot might take 3 or more before he drops.