I saw an egg a while back about using an air compressor as the power for a dart gun. That was a great idea but not terribly portable (or silent when the tank fills). I thought of a fix... using canned air (the kind you buy for cleaning out your computer). You could tape the straw nozzle to your dart gun (simplest method although you could attach it with caulk or a rubber stopper). Just make sure no air escapes out of the seam.

Its powerful, portable and silent. The longer the barrel, the more accurate. The narrower the barrel, the more powerful. You would have to muzzle-load the dart gun unless you made special mods (I\’ve seen very clever ideas on that here too). It\’s inexpensive and easy to assemble. Anyway, just a thought which I hadn\’t seen posted here. Thanks for reading and thanks for all the good ideas!