my second 6mm. custom QEV sniper airgun updated

[bladeul2006]

the modification looks like this
I attached the tank to the chamber, and as a pilot I used a slightly different type of Schrader valve used in my line of work.
The problem is that once I fire it goes boom like expected, , but after the piston does not shut instantly, and it goes like "sssssssshhhhhhhhhhttt....". I mention that I just tap the pilot to fire. I intend on making something like a hammer to fire.
Can anyone tell me the possible problem ?


PS: I use unregulated co2 on this cannon
how tough must the spring behind the piston be ?

[bladeul2006]

problem solved by sandpapering the piston a little and by replacing the spring with a stronger one. triggering system is next

[jackssmirkingrevenge]

replacing the spring with a stronger one

hammer spring or piston spring?

[bladeul2006]

piston spring, I haven't made the hammer yet

[bladeul2006]

I got a nice big piece of solid wood, and I probably start making a stock for this airgun.
some pics of current work, the pilot is a Schrader valve (hope I spelled it right), which is going to be pressed by a old/western style pistol hammer (which is in work at the moment )