double post, i know (stupid computer wont let me edit for some reason) Thanks Technician for pointing that out, I should definitely fix the piston itself first. I'll try using bathroom caulking to fill the threads of the bolt and see if that helps. And i should've checked the barrel first, i'll try ...

If i put a big piece of wood in the pilot area behind the piston, wouldn't that stop the air from flowing? or would the air just push it forward with the piston?

and for a bumper could i just use part of that hose in the first picture?

Ah I see, that makes more sense. I'll figure out some way to seal it eventually, but any tips on doing it would help me finish this cannon a lot faster

So as for the pilot volume being to large, is there any way I can fix that? And about how big should it be?

Is it really? damn, everything's already glued

how can I make my pilot volume smaller?

Try using a piston that has a flat sealing face. Not one with a giant hole through it. :wink: i made it have a flat sealing face, I cut approx. 5 pieces of rubber and bolted them onto the wheel. here's the pictures, btw http://i593.photobucket.com/albums/tt15/beardie6767/IMG00348.jpg http://i593.ph...

It's not a leak in any of the joints, the air is coming straight out of the barrel, like the piston isn't properly sealing.

I'll go take some pictures now, be back shortly

Ok, I've been having some issues with my first piston valve not sealing correctly. I made a coaxial with a 2 inch barrel and a 3 inch chamber, and used a longboard wheel with a couple sheets of cut rubber for the sealing face as a piston, but it doesn't seal. Whenever I put air into my launcher it a...