A5 Air leak.. Need Help

i bought a new A5 about a month ago and went out with some buddies to test it out and i really love the gun it shoots amazing but then i got home and was dissassembling it to clean becuse we played for a good 6 or 7 hours and a washer and O-ring fell out i read the manual and used the diagrams in the manual and put everything back together as it was shown in the manual and yes i made sure to put the washer first then the O-ring and i made sure to lubricate the O-ring before re installing but then after i re assembled the gun and hooked up my HPA tank there was an air leak that seemed to be coming down the barrel so i got an A5 O-ring kit and replaced every internal ring in the marker and made sure to lubricate every one but i still have a leak any suggestions??

TY for the reply but i had my buddie look at it and apparently my valve plunger was malfunctioning some how and he worked his magic on it for me and now its holding air like its brand new again. thanks again though im new to paintball and to the forum but there is alot of helpful stuff on here

he said that the plunger wasnt sealing properly and he disassembled the valve and in side the valve there is a little brass looking washer that kinda looks like a top hat and has a small ridge on one side and he said the side with the ridge is supposed to be up so that the plunger can seal against it and i had it flipped upside down and it wasnt allowing it to seal properly so he swithced and and put a small drop of oil on it and put a little bit of pressure on it inside the valve body to seat it and he put it back together and ever since it has worked perfectly