Fair enough. I guess you could always sell it for a few hundred bucks if you get bored with it as your cannons are quite powerful pneumatics and aesthetically pleasing as well as fairly ergonomic.So, I have 85% of what I need sitting there. It kind of seems like a waste to not build something with them
If you want to stick with pneumatics; build a large piston valved launcher.However, I am totally open to building something new.
What are your thoughts on what I should build?
If you want to try a combustion: a 15" x 4" chamber with a 6' golf ball or tennis ball barrel with metered propane or MAPP gas and a 12v fan will be enough to impress. Something like that would be good if you want decent performance but better portability.
If you want to try a hybrid I'd recommend a burst disk hybrid using a union anywhere from 3/4" up to 2" in diameter. You want supersonic golf balls or tennis balls, go with a union at least 1.5" in diameter. If you want supersonic ball bearings, stick with something 1.25" or smaller. Hybrids can also be quite portable, similar to a combustion except you'll need a track pump if you're not near a car or mains.