This is my marble rifle made with pvc. It has a uses a ball valve and fires you geussed it marbles. It has a silencer that works and is not just for looks. Hay if anyony has a rifle like this I'd like to see it so post some pictures and have a look at my instructable http://www.instructables.com/id/Pvc-AirGun-Bullets/
And tell me what you think about them!