Was this a conversion? My guess on your initial problem was that the spring wasn't actually going into the trigger group. For the leaking issue, does it stop when you pump it again or just vent all the way out? The only seals that can really cause a huge leak on those cart valves would be the 12g face seal and the "cup seal" on the valve.
Note: While I would love to take credit for his work, I am not associated with Mad Customs!
Originally Posted by senghing27
You can contact BigMatt-MadCustoms in his MCB forum