This design was based off of Frockies' and Rag's copper cannons. It has the handle of Frockies' and the pistonvalve and soon to be qev piston of Rag's.
Starting with the barrel, its a marble barrel, alum to be exact. its 50" long and is a bolt action. the alum barrel slides in and out of a .5" pvc section and i have orings in there for a good seal.
my piston valve is a 2" black steel tee. the main piston housing is a piece of 1.5" galv pipe. inside that pipe, a 1.5" end cap with a sealing face and bumper. i added an oring to make the piston more airtight.
the pilot right now is just a .5" ball valve but in the future (tomrw) my .5" qev comes and i'll put that where the end tee is (where the hose comes from after the piston) and then that qev will be piloted by the .5" ball valve and the qev will pilot the piston .
Main opperating pressure is 150psi
My main ammo is 4g marbles, ggdt says ~760fps
Another barrel that i am looking for is a 6mm bb barrel and ggdt says 1407fps for a .12g bb
i ordered a low power scope and i will attach it to the top.
here are some pics










