Pneumatic Gun

I had some extra time yesterday so I made a simple PVC pneumatic gun. The design and shape of the gun is my own, but I'm sure that similar models exist. The trigger system consists of a sprinkler valve and an air blowgun, instructions can easily be found through Google. It's meant to be held with two hands, hence the sideways valve. The primary air chamber has a volume of 44π cubic inches, with the extenders and fittings adding another 16π cubic inches. The barrel is 11" of 1/2" PVC, and the male threaded adapter allows for an easy way to change barrels. I also made a barrel that is 4" of 4" PVC, meant for water balloons and the like. The 1/2" barrel can shoot nerf darts and custom arrows with limited accuracy, but I haven't seen results at over 80 PSI. At 80 PSI, it sends whatever is in the barrel completely flying. Pics: