By the "click but no firing" issue, do you mean you pull the trigger but nothing happens?
I got a set of shims for 3 bucks, I got cheap VS shims from AirsoftDepot because i don't see the difference in shims. If a gun is lipo ready, shouldn't that mean it can easily take 8.4?
Guardians of Asgaard - KF32
VFC H&K 416C
VFC KAC SR16 JL Billet SBR
TM FN Five-seveN