There are several threads here around defense against a dog. Here is a video and story about one encounter.
Some items to think about…
- people had been physically attacking the dog (punches, shooting with paintballs, referenced but not shown on video) before the armed citizen intervened and those blows had no effect. It is possible pepper spray would have had no effect
- the armed citizen told everyone to get clear before he fired
- look how close the dog (target) is to the child, the dog is shaking the child (erratic hard to predict movements)… you need a high standard of marksmenship to hit the dog and not the child. Kudos to the armed citizen for making the shot
- a bystander was hit by shrapnel