A different application from your idea.
The trigger you actually draw is the initiator of the recharge of the repeat hybrid. It is the mechanical locking of the piston, which allows it to move to the right, by the action of the spring, and then, to the left by the action of compressed air. To fire, the trigger is the piezoelectric.
What I have added is a "StrongBoy" type mono-pumped weapon with a side bb`s loading system.
The firing sequence is: Press the green "trigger", which you drew, and the weapon is traced, and then press the button on the piezo spark arrester, and firing occurs.
What I write is off topic, but it was just an idea.
With a 2 "piston in its design, and about 6 bar of air pressure, being the hybrid's piston 1.5 cm in diameter it can be compressed to about 68 X ... nI CRAZY WOULD USE THAT PRESSURE, but if you use less is feasible to work The part of the hybrid is proven and works well What you designed, I am totally sure that it works, for the clear and simple design.
I leave an adapted drawing, to explain better.