I noticed that a lot of new members wants semi auto, and I saw a lot of explanations about slid valves and 3 ways. As I wasn´t able to find these parts, I decided to find a way of make a semi auto from a mechanic way instead of pneumatic way. So I had this idea, as most people here uses qevs that are piloted by a blowgun, by connecting the blowgun trigger with a ball valve for re charging the secondary chamber( when you pull the blowgun trigger, the ball valve closes, when releases the trigger, the ball valve opens with a spring) as the ball valve doesn´t need to be fully open to recharge the secondary chamber quickly
this system should work with blowgun piloted self close qev/piston valve or bb guns what uses a blowgun as firing valve
If I wasn´t clear enough here is a diagram, feel free to ask questions
"yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " 
1/4 ball valves are really easy to open, so you can use a weak spring...
