Cannot discharge a gun unless your 600ft away from a building. Thats it?
Geez I should move to Virginia.
Personally, I'd get in touch with a Private Investigator.
Tell him whats going on and get him to set up video cameras
and collect footage on just what this kid does.
Most of these guys are more than capable of getting the job done.
Law enforcement aren't going to do much for you.
If he's shooting at birds, (robins, blue birds, animals, that are protected and illegal to shoot) I'd take this route over trying to get him to stop shooting on his own property.
It may cost a few grand but it will work I'm sure.