Before we begin, there is a point I would like to stress- and that is Stupid hurts. You are building an air cannon (this could be used as a weapon). Because this cannon will belong to you, and it is your cannon, if you decide to do anything..................well, stupid with it, it's also your stupid. So it is your cannon, your responsibility, and anything you do with this thing is your consequence! That being said, END DISCLAIMER, BEGIN INSTRUCTABLE!!!!!!!!
In case you don't know how these amazing devices work, well obviously they use air (DUH-air cannon). Air is pumped and compressed into a chamber on one end of the gun, and on the other the ammunition is stuffed into the barrel. The barrel is connected to the pressure chamber via a ball valve or an electric solenoid valve. The valve lets the all the compressed air flow from the pressure chamber to the barrel, pushing the projectile out of the barrel and into the next county.