
The chamber is made from 3/4" pvc, and the barrel is a 12" long piece of stainless steel pipe. I'm not sure of the exact diameter of the barrel. I just went into Ace with a couple of airsoft BBs and looked for the best fitting pipe

The piston is made from hot-glue, which was cast into a section of 3/4" pvc for the mold. The sealing face is a piece of neoprene, glued to the front of the piston.
The highest pressure that I've taken it up to is about 145-150psi. The coupler on the front of the gun looked a little suspicious to me. I got it at Ace hardware, in a bin that said that the couplers were pressure rated, but the plug doesn't fully fit into it, and it looked a little short in general, so I think it might be DWV.

<a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... erview.jpg" height="200" alt="Overview next to a ruler"></a> <a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... Valves.jpg" height="200" alt="Pilot side"></a> <a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... Muzzle.jpg" height="200" alt="Muzzle"></a>
<a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... ryHole.jpg" height="140" alt="Entry Hole"></a> <a href="http://i119.photobucket.com/albums/o139 ... .jpg"><img src="http://i119.photobucket.com/albums/o139 ... itHole.jpg" height="140" alt="Exit Hole"></a>