I was going to say that I rather enjoy shooting pingpong balls filled with black powder, but now I think I won't say it. [troll]
They ARE fun to shoot, though!
Hey, what about those exploding targets? If they're legal, why not a modified pingpong ball?
I mean, heck, I've got to find SOME safe way of disposing of all this old black powder, don't I?
Actually, you'd be surprised how easy it is to get an explosives handling permit, anyway. It's easier than a CCW permit in some states.
Old cans of diced pineapple (or other foods) that are beginning to swell make fun targets.
Bic lighters.
Full cans of cheap spray paint!
Shotshell primers (live ones) taped to a board.
Get those toy gun caps in red paper tape, peel off one roll, and tape it to your target board
and nail it with something big, like a 12 ga. rifled slug. The boom at the target may be louder than the boom from your gun.
Those caps are awesome, if you blow a roll at a time. Drop a roll on the sidewalk (standing up) and nail that sucker with a sledgehammer. If you're not wearing ear protection, you'll wish you had. Neighbors will come out of their houses and look around. Act innocent.
It's also fun to tape a long string of primers to a railroad track, back off, and wait for the train. Space them a couple of feet apart.
CJ