sirjonas

I can't get my PMI GTI to work. The first time i tried it, it sounded like the air was just leaking out of the barrel and it would not fire. so after losing the entire tank of air i went and read the manual and found out that i had to cock the marker first. second tank of air worked good. i just had the 4 oz tanks on first, because i did not find a spot to refill my 9 oz tank. so after i got my tanks refilled i went to try and see how it would work because i just went out and got a 14" barrel and a spring set so i could set up the velocity for the maximum. now all it does is shoot the air out the barrel again. it does not matter if i cock the gun or not first. now i did take the gun apart to see how everything works and to find out the location of all the springs. now i tried flipping the valve around thinking that maybe for some reason i put it in backwards, but that did not seem to fix it. i tried replacing the o-rings on the valve but that still did not work either. What else could be causing the air to leak out the barrel? Could the blue o-ring on the hammer be screwed? i looked at it and did not see any problems. I do not know anything else that it could be. any help would be really appreciated thanks
Jonas