Okay, I read 2 other threads of this calibre and my valve is not upside down, nor is my bolt. Okay so.. the gun gasses up fine. bolt goes back. but when I fire the gun, the bolt only seems to travel quarter or sometimes half of the way of the travel it should. My high pressure reg shows 400PSI and i've reset my LPR multiple times by turning in until it leaks then backing it off 2 turns, I dont' see very much drop on my gauge during cycle.. and it seems like it has full power to everywhere.. but no air comes from the barrel. Im completely stumped! what should i try?