Solenoid needed for HPA single-shot sniper - ideas?

[swatti]

Planning on building a "bolt-action" sniper-rifle using existing HPA-rig i have...

What i need is a solenoid for the air.

Would this work:
http://www.ebay.com/itm/1-4-2-Way-Norma ... 1516038925

Do notice the BB will be loaded via bolt-pull so it needs only one-in-one-out solenoid.

Also, any suggestions on a circuit to time it? Needs to be easily adjustable timing. And if that solenoid works with 12v, will it function at all with mere 9v as i was hoping to use 9volt batteries. Other option is a regular lipo-battery.

[Doodmens]

How HPA is your HPA? The regular chinese valves generally don't take more than 10 bar. For the timing I recommend you use a microcontroller such as an Arduino, which are cheap (if you get a chinese ripoff), easy to program and use