I was reading this thread and the idea of a very low pressure pump sounded interesting.
I had previously thought of making a pump that used a system besides a popit valve. I've sketched out some ideas but before I draw something up in Solid Works I thought I would ask here to see if anyone had tried something similar before.
Plan: Pump arm would have a rod which went backwards to a bolt. The bolt would only be responsible for cycling a new round into the barrel. Behind the bolt would be the firing system. My goal is to have a dump chamber that seals off the air input as the firing is initiated. I wanted to actuate it with either a 3 way from a cocker inside the grip frame or a pneumatic trigger of some kind. Velocity would be adjusted via HPR.
Concerns: I don't know if the speed the trigger is pulled will effect velocity.
Since the pump stroke does not actually recock any part of the firing system you could continually pull the trigger releasing air but no paint. You may also be able to pull the trigger and release air while the bolt is not fully sealed forward.
So any suggestions? Has this been tried and proved to be unfeasible?