Here is what I have made as my latest.
A bolt action gun, fully portable, operating at 120psi. My clippard tank is the biggest limitation, rated for 250psi, so I do not see a need to go too much higher. I have a DCV and QEV operating the pneumatic system. I am estimating 300fps.
After some test shots at 20ft at an empty paint thinner can i caught ricochet and got a nasty welt, so this thing has some power. I attempted at sights and bi-pod for the first time and both are working somewhat.
What do you guys think, I have learned a lot form this project and I hope to learn more from the comments, so have at it

UPDATE:
Damage pics on a paint thinner can, ranging from 130psi to 120psi with 6mm air-soft pellets