SpudFiles

i created a coaxial piston valve cannon and when i let the air from the pilot out the piston still stays forward.... how can i fix this

Use the search function.

members have been dealing with these issues on here since the dawn of Spudfiles.

here are a few example threads I found for you:

http://www.spudfiles.com/forums/piston- ... 23583.html`

http://www.spudfiles.com/forums/piston- ... 20618.html

http://www.spudfiles.com/forums/trouble ... 20113.html

basically too much blowby on the piston or rather too much compared to the pilotvalve's flow causes these issues.
Snug fitting piston, still able to slide... and a good ( big/fast) pilotvalve fixes it.