I just had time to share this with you..
Cannon name: Lupara ( Sawed-off III)
Cannon type: Single shot Pneumatic Sawed-off
Pressure used: Up to 50 bar
Valve: Modified QEV, now chambersealing!! High flow...
Caliber: 16 mm smoothbore ( perfect marble fit)
Stock/handles: Hardwood
The handle used to be bike handlebars, tapped to 1/2".
Ballvalve needs to be replaced, it leaks.
All hardwood still needs sanding, lacquer etc...
I lathed out the exit port on the QEV from the inside, leaving just a small ridge, to make room for the Nylon piston, and create higher flow than the original setup.
This also gave me the opportunity to get the 3/4" chamber and the barrel as close together as possible.
Piston has a 1 way rubber flap-for sensitive pilotting.
No idea about the performance but experience tells me at 50 bar it will be adequate...
I'll try to get the look up to Shatterhand level later, maybe add a triggerguard, that sort of stuff...
No time for testing...I'll be back in two weeks..
And off to European Pumkin Chunkin the next day..

Some early pics: