Ball valve mechanism?

[Urban Ninja]

I am making a steel shotgun. I am using a ball valve due to the ease of getting it, low cost and can withstand very high pressures. But i really want a trigger to so it can be accurate and fast opening. Would this work? (Picture).
It is a tesioned spring when cocked and attached to the ball valve with string. When the trigger is pressed the ballvalve quicky opens.
Does any one else have any other ideas? I really need a trigger so any help will be appreciated!! Thanks a lot.

[Rambo]

That was my idea.A combustion operated cilinder shoud be better then a spring may be.But I agree that it is very inpracticle.

[Urban Ninja]

Have you already posted this idea then (Spring)? If you have sorry, it was just an idea I had been playing with.

[Benny]

you could use a pneumatic ram.

[Rambo]

I don't remember waht I've posted but I'm pretty shure that I didn't post this.