A-5 Low pressure Kit questions

OK , My brother has been playing  with a JT- 4.0 Xcellerator for over 2 years now ( A hand-me-down marker after i bought a 2k3 Shocker )

The JT has a 14 in progressive and a 4500 PSI Smart parts Max-flo Manifold and a BSA 30mm Reddot . Believe it or not the thing is dead on accurate at 70feet with a 2-3 inch spread in zero wind. Only problem is the rate of fire and the range was buggin him. So he saved up his money and after after eyeing the A-5 for like a year and a 1/2 he finally got it.

The original plan was to get and A-5 , Flatline , E-grip , Low pressure kit , and remote line.

Anyway we tried running the Maxflo on the tank  set with 325 PSI Output pressure thru a remote line and directly into the Tombstone but with the Low pressure bolt and valve assembly in the power tube. Completely  . We noticed a air leak that was leaking down the barrel . Suspecting a o-ring , we took it apart , inspected and re oiled all oring , and tryed again , same deal , leak was still there. suspecting it was something to do with the Lack of the Vertical low pressure chamber , we installed that , still leaked. We then Uninstall all parts and returned the A-5 to the factory setup , old bolt and all and it worked fine with no leaks. Then reintalled low pressure bolt , Low pressure chamber and it didn't leak then , we then shot off a hopper with much excitement . But as we finished the hopper off with about to balls left the leak came back. 

Has anyone Else experimented with Low pressure setups , not using the tippmann vertical chamber ? Or had strange problems ? . If i do need the chamber and the secondary reg , Which Regulator works best with the Tippmann Low pressure kit ? Is it sound more like a Bolt and oring problem for the leak then a Air pressure issue ?

Thanks for reading my Novel , hope someone can help us .