I build it in about 1 1/2 hours and it is my first coax ever.
Total length: 99cm
Chamber: 1", 40cm + 20cm galvanized steel
Barrel: 15mm, 78cm long
The piston is basically the one I described on this how to....
http://www.spudfiles.com/forums/self-cl ... 17609.html
The barrel support...
13cm ~ 5.12inch nail dart

Some damage (unfortunately the flyer failed)

It was pretty fun to build this and the power is better than I expected for a first build coax.
Hope you like it







