A friend of mine had a bull mastiff growing up that was a great dog. One day two lowlifes broke into his house while nobody but the dog was there. Unfortunately, they found the dog dead when they got home. However, the dog had latched onto one of the perpetrator's hands, and it was still inside the dead dogs mouth! They fingerprinted it and caught the guy, who then rolled over on his buddy. The whole point of this story, I forgot, is to say the dog suffered 3 heavy blows to the head from a crow bar and multiple knife wounds, and still wouldn't release the hand! So a .22 might not work on all of them. Sad story, but a damn good dog!