If you’ve always wanted to “shoot an object at 140 MPH over 500ft”, then this gadget is for you. Full instructions here. Video (fake infomercial) after the jump.
The launcher will shoot anything from a golf ball to a tennis ball at extremely high speed and extremely far. For wadding, a Pringles can or tennis ball can work best. For the valve, use a solenoid or metal ball valve at least 1″ in size. Ranges vary by the pressure used and what you are firing