SpudFiles

well im making a coaxial pneumatic with a 3" camber and a 1" barrel. that would mean i need a 3" piston. my idea was to get a 2" cap and a 2" plug glue them together and use them as the back bone to a 3" piston, then i would put them in a section of 3" pipe and dump some hot glue in to make the piston. now i have a question; would this work? or would the piston be to long?

cannon length - 40 inches
camber diameter - 3 inches
barrel diameter - 1 inch
piston coaxial

ps- how should i support the barrel inside of the chamber?

Tye piston will work fine, just leave enough room for it to slide back.
As for the barrel support, just use pieces of pipe, for that gun, I'd use 3/4" or 1" PVC, not sure which.