@JSR: I've understood now your suggestion, as this is my first build I'd like to keep it as simple as possible (within my requirements) avoiding moddings for now, so I think I'll go for the 3 way pilot valve (I still have to find a place to buy it, in Europe I've found technobotsonline.com but I'll ...

I'm not sure to understand your suggestion: for "reservoir" you mean the regulated shooting chamber or the HPA reservoir?

thanks to all for the comments

@seafroch: I planned to use brass just because it's the material in which I've found pneumatic fittings to be most readily available, but I wouldn't mind spending a bit more for steel ones, if I can find them. Do you think brass can explode or something like that ...

Hello, first of all sorry for my bad english but I'm not american...I've come across this site looking for parts for my airsoft svd dragunov (which I use mostly for plinking) and what can I say...I think i'm addicted.
So what I want to do as a start is to build a BB "single shot" shooter, capable of ...