Intro: Electric Pump Powered Spud Gun
It is a simple ball valve pneumatic spud gun but instead of a hand pump it uses a 12V electric pump (originally a car pump), I reconnected it to a 12V battery I had laying around (as you do), it uses a 2.25L bottle for air storage I suppose. By the way it uses a hell of a lot of duck tape! just something to keep in mind. it refills in about 10 - 15 seconds, compared to pumping for about 1 - 2 mins.