Hi Lee,
Sorry to read that you have been having issues, but DYE and our Accredited Dealers always fully back up any of our products. Ash has already posted on this thread offering his advise and email if anyone should need technical assistance.
In regards to your PMR, if your pressures are set too high it is bound to blow orings. There is no common problem with these markers, there are 10's of thousands out there being used by happy customers all around the world.
Once the gun is set up and working well, usually simple regular bolt servicing and lubing will keep it running perfectly. There shouldnt be a need to adjust pressures apart from tweaking of FPS for different paint/barrel matches.
Please feel free to drop us a line at DYE on 0208 649 6330 to talk through anything.
Best regards,
Tommy