Was there a noticeable loss of power from reducing the chamber? I like the look, much cleaner looking. Easier to service the piston if needed. I'm assuming the barrel will need to be shortened. I am building two more for my friends, I think I will make one with this modified design.

I added a rubber gasket to the rear of the piston. Works great now.
Thanks.

I have a wood piston that fits very snug, should I add an o-ring to make it even tighter?

I just built a cannon based on your drawings and plans. I tried to make it exactly like your design. For the piston I turned a block of wood on a lathe, it slides easily in the gun. I used a piece of rubber on the face and it seals well. However, when I activate the pilot the chamber air goes out th...

I wanted plastic to help keep the weight down. I guess a smaller 1" metal valve would weigh the same as a 2" PVC.

OK. I will try a smaller valve. Thanks for the help.

It looks as if this ball valve is a solid piece. We were unable to even close the valve once with our hands. Maybe I just got a bad valve. They had to special order it so I couldn't try another one.

I bought a 2" PVC ball valve to vent my chamber. It is very difficult to open and close. I tryed to lubricate with oil and it did not help. Are ball valves normally this hard to open and close? Maybe a smaller one would open easier.

I also have a golf ball and softball barrell. 10% more might be worth it.

I currently use propane on my gun and may switch to mapp gas. I use a meter and a fan. Is the Mapp going to have a noticeable difference. 2nd question, the propane is 4%, what is the mapp percentage?

Thanks,
Pibster