My classic spyder is leaking air out the barrel

[FEZ1992]

I just bought a classic spyder paintball gun the previous owner didn't really take much care of it friend of my help me clean it and change the o-rings... When I put a co2 tank on it it was leaking air out the barrel...i already had a Tippman A5 but never encountered this problem... I need some advice not sure how to fix this problem
http://www.google.ca/imgres?imgurl=h...ch&um=1&itbs=1
My spyder looks similar to this one except the barrel is different and mine has a double trigger need all the help I can get to get my gun working at full potential

[bigred76]

Change out the cupseal and make sure you didn't shred the front valve oring. The cupseal is most likely the case, and I would attempt to replace it before checking the valve orings. The cupseal could be damaged and you can't even really see where. After replacing the cupseal and reassembling: put a drop or two of oil into the ASA, cock the bolt, screw on the tank, and dry fire the marker without barrel or hopper in a safe direction. If it's still leaking after that... check the valve orings.