I know an old sheep rancher in Colorado who was surprised by a bear while on horse. They rode right up on the bear. The horse spooked and threw the guy off. As he was falling off he had the presence of mind to pull his rifle from the scabbard. Like most old woodsman around the west, his rifle was a single shot 22. He regained his footing and while the bear was occupied with his dog, he shot the bear in the head. The bear was un-impressed and lunged at him pinning him to the ground. By this time the young pup he had along started biting the bear on the butt. The bear was on top of him looking back biting at the dog. The guy was able to fish a second round from his shirt pocket, load his rifle and shoot the bear through the bottom of his mouth which resulted in a dead black bear landing on him. When he tell the story it is quite comical.