SpudFiles

I know you won't get many shots out of this but here's my idea, build the whole frame of the gun out of pressure rated pipe and pump the air into the frame chamber. This would be easy to do with this design, but maybe with slightly bigger pipe.

http://www.spudfiles.com/forums/viewtopic.php?t=148&

people have already done this. if you look around for strafers youll find them. theyve also incorporated a small bike pump into the design. Theyre like strafer pistols