I saw a buddy of mine have his contour hd lens blown apart by a paintball.. Walked off the field with a hand full of parts. That looks like a pretty stellar
First thing you need to do is diagnose where the problem lies.
If you hold the trigger in all the way, does the leak stop or does it sputter?
I assume you mean you have a ULT installed. Or, do you mean you are just using ULE rail and aluminum body? There are a few things it could be.