I agree, I have several of the starter guns for dog training scattered around the basement, garage, and shed. That appears to be an older starter gun by the appearance of the frame, hammer, and barrel, silver colored ejector rod (made of zinc in mine, the newer ones are black plastic), and by how close the cylinder is to the frame (no forcing cone). I'm surprised the poster did not notice the "barrel" is not drilled all the way through. The starter guns could charitably be called "cheap" which is why they are scattered all over as I canibalize one to fix another. If by chance this is a "real" firearm, I would definitely deactiveate the firing mechanism pronto as it would probably be dangerous to fire.
Starter pistols typicaly had 8 rounds for the 8 events at a track meet requiring a start shot. A drilled barrel was common on older models (1970 or latter). 8 shot are also good for training hunting dogs, the dog will watch the shooter and if they reload each shot the dog will know when to start before the shot.