Are you lubing after 250 pellets? I use two drops of oil down air intake hole. I've improved my trigger by putting a washer over the post that holds the spring, then attaching the spring to the washer, thus lightening the weight. This has made a massive difference to the trigger pull, it was too heavy for me before. Also, if its a sticking valve, you could try slightly opening the barrel arm with the muzzle pointing up, the put a drop or two of oil on the breach hole, then fully cock so the oil is sucked into the valve system. A good lube sometimes sorts these problems. My PR45 is great now except for a crack in the plastic frame, just under the pivot pin above the grip. Don't know what's caused that. ATB. Pete.