20mm Copper/Brass Piston Cannon

[jmadden91]

Well it has been a few years but I had a few parts laying around and decided to have a go putting together a 20mm piston cannon. It's nothing that hasn't been posted here a million times but it kept me busy for a while. Still needs some work, a paint job for one. Making a suppressor at the moment as well as it is bloody loud.

Specs:

Barrel: About 600mm of 14mm ID Aluminium
Chamber: 450mm of 20mm Gal Pipe
Piston: Wood (waxed then heated), o-ring seal
Operating Pressure: Usually around 200psi with a bike pump, will go higher when I put together a new fridge compressor.

Full Length:


Valves:

Piston:



Breech Closed:


Breech Open:
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[jhalek90]

looks good. The piston looks very pretty.

Any chance of a video?

[jmadden91]

Thanks mate, Ill get the gopro on it tomorrow, want to try out the slowmo

[jmadden91]

Well this thing has been a pain in the ass, it has blown the seal off the face of the piston a few times, the piston went through the bumper and destroyed the ball valve another. So I ordered some HDPE rod and made up a nice new piston, redid the seat, and made a new bumper. Works perfectly now, even at very low psi. Still needs some paint, but im not too interested in how it looks.

Valve open:


Valve closed:


Piston:


Full Length:


and a few test fires at 100psi:

http://www.flickr.com/photos/46809212@N06/6949549730/

http://www.flickr.com/photos/46809212@N06/6949549738/

[jackssmirkingrevenge]

Basic but well put together, good job what's inside the suppressor? Or is is just a hollow tube?

[jmadden91]

Just cotton rags rapped loosely around the barrel. Pretty effective at lower psi but at 200psi and beyond it's not much use

[jmadden91]

Sorry guys more pics, different barrel on it here. Few damage shots as well, ammo was marbles hotglued into the top of short lengths of conduit. Missed the target and it blew through the fence a few times.. wasn't expecting that haha.

[jackssmirkingrevenge]

Missed the target and it blew through the fence.. wasn't expecting that haha.

Excellent, mark of a true spudder