Although my .177 HW45 was recording high velocities (600fps/5.6ft/lbs) it was Dieseling on every shot, I know this is normally the case with the PTFE Piston Head on the HW45 but it was quite inconsistent.
I purchased a new Spring and Piston Seal, now fitted the Pistol is smoother and a lot more consistent but the power is down to 4ft/lbs, is this usual?