It's build all out of copper pipes. I use a 85 cm, 22 mm pipe as the chamber, and a 15 mm 100 cm pipe as the barrel. I slided a aluminium tube into the barrel, to make my breech loading system.
The valve is a barrel sealing piston valve. My goal was to keep the pilot chamber as small as possible. It's about 5 cm long, and 22 mm wide.
This is my piston;
The rubber sealing comes from a syringe.
As the trigger valve I use a modded blowgun.
It shoots very well, and I'm going to upload some damage pics soon.
