
Reffering to the picture, the guide rod and return spring, however, would create some weight for the piston to have to deal with while it is opening, so i suggest lightweight material for the guide rod, aluminum tubing maybe. Also the proper return and catch springs for the piston would have to be figured out based on the pressure you wanted to use with this valve. BTW, the picture doesn't show this but i was planning on using epoxy or something strong to hold the springs down to the endcap so they stay in place. Also, the return spring for the release pin pushes the release pin back up to catch the end of the guide rod (when it returns to closed position) when you release your squeeze on the trigger. This allows for semi-automatic possibilities if you have flow regulated air coming into the chamber or something similar. Check it out and let me know what you think, any questions, comments, faults you see?