Go through this checklist first...then report back with your findings.
If the bolt has been disassembled recently, make sure that it has been put back together so that the pin is the right way around, so that the inlet is facing down. Unlikely though, as the velocity isn't particularly low.
Shooting very small paint through a large bore barrel will tend to reduce your velocity.
Check that the LPR is assembled correctly, with two springs, one either side of the piston.
Make sure that the spring cup inside the LPR is the right way around.
Set the LPR to the stock setting, with the tip of the adjustment screw level with the tip of the LPR cover.
Make sure that the LP hoses are unblocked and that none of the hose barbs are blocked or bent.
Replace the rammer o-rings.
Only ever oil the rammer o-rings, never grease them.
Replace the o-ring around the rammer cap.
If the marker has the Etek STAR frame, and the QEV is installed, check the QEV diaphragm is in one piece and that there aren't any excessive signs or wear, or any cuts, tears or holes.
Make sure that both banjo fittings are screwed down securely.
Replace the o-rings around the rammer housing.
Make sure that the solenoid has no signs of screw damage (beyond cosmetic scratches).
Make sure that the valve guide/rammer housing hasn't been installed upside down. Again, unlikely, as the velocity isn't that low.
Make sure that the seal on the tip of the HPR piston neck is there, and that it is clean and undamaged.
Make sure that the port on the end of the HPR adjuster screw is clean, and that it isn't scratched or dented.
Make sure that the HPR output pressure isn't set too high, as this can reduce velocity.
Set your dwell back to stock if it has been lowered.
Try a fresh quality battery.
