how does the trigger system work in the qev 3way pilot valve setup,im out of my area of experience since i do simple pheumatic cannons

i need th air to burst out since it will be a high powered aisoft rifle but i am unsure of a magazine or loading system.i would like this to be semi auto but the ...

im currently using the general design of nighthawkinflights bbmg here

[youtube]http://youtu.be/ME1BcEcBD9I[/youtube]

but i have a paintball tank variable of an output from 0-300 psi ive been using a blowgun valve but its limit is 80 psi .are there other small easy to release valves?

p.s.im ...