Pump Action Bolt Gun

[Atlantis]

I had no idea what to name this thing. Anyways, I took a look at http://entertainment.howstuffworks.com/ ... 3d-gun.htm and came up with an idea. I took the loading mechanism from Galfisk and the bolt from Clide, when you pump the gun the ammo bolt moves back and pushes the air bolt back until the trigger holds it in place, the ammo bolt is pushed forward to load a shell but the bolt stays sealing the air chamber. When you pull the trigger the bolt is released and the air pushes the bolt forward and launches the potato. If I ever try any of my ideas this will be the first, if it does get built it will most likely be turret mounted to make more room for the ammo and also due to weight reasons. Any help or suggestions would be appreciated.
http://home.no.net/galfisk/images/pumpgun2ani.gif
http://www.spudfiles.com/forums/download.php?id=70&