Yeah, me and my brothers use to buy black powder at the Gibson's department store near our home. We would drill a hole in the end of the empty CO2 cartridges from the pellet pistols we bought, fill em full of the black powder, and plug the hole with a Mule Kicker firecracker. Then we had a firecracker that would really make some noise.
I fondly remember the BB Gun wars we had in the neighborhood. Somebody always violated the one pump rule though. Nobody lost an eye either.