i haven't posted in a while as i have just started working full time.
Patent Pending.
i have upgraded my old gun, it now has about 300% improved air flow
old gun: http://www.spudfiles.com/forums/semi-co ... t8892.html
i did this by removing the bolt plug (purple thingy in the diagrams on above link) and adding a small homemade pneumatic ram that is connected to the firing chamber. So when it is pressurized the bolt moves forward when the pressure is released by firing the bolt is pulled back.
i have successively fired this in semi auto.
it has a very loud hissing sound due to the poor seal in the ram and a loud bang with each shot, so i cant really use it at home. it has a slow fire rate about 1 shot every 3 seconds but i should improve this by adding a smaller firing chamber and weaker spring inside the ram. my ammo is 15mm wood dowels, amazing fit inside the condute.
You can use this design as long as you do not sell guns or clame this design as your own.
sorry about the bad quality pics

long trigger hose leading to sprinkler valve for safety. other long hose connects to the scuba tank. short hose leads from firing chamber to back of ram.

this is the ram that screw holds the front end cap on it.

how the shells sit inside the mag

this is the connection for a BCD which connects to an scuba tanks. puts out about 120 psi.

forward view of ram and blot
crappy video
http://s214.photobucket.com/albums/cc82 ... Video2.flv
you can kinda see the shells ejecting






