well, here's my question:




what causes air to get over there? I don't see how the shape with a void there is formed.
Usually, when you stick a piece of pipe into a tee, there is no such protrusion of the barrel into the chamber.

ummm... two inch ball valve, like my friend did?

so what is a good bumper? spring? foam camping mat(have too many of those around)?

yes- its my first piston, i don't see how to get the air on the ummm... non-pilot(?) side of the piston. plus, the area that the pressure is applied to is so much smaller, doesn't this lead to slower opening times?

I've built a couple of pneumatics so far, they had ball valves shot about 600 feet. so i have *some* expierience. I want to improve on these. I plan on having a 2"x5' barrel and a 4"x2.5' chamber(or equivalent of 3" if i can't get 4" pressure rated) the goal is to have a 2" piston valve. probably ch...

so, i am going to be building a 2" piston.
two questions:
1) what is a good piston material for 2"?
2)why does a chamber sealing gun need an O-ring?