Hey guys, small update.
Last week I shimmed this gun (since it came with no shims and the sector was making contact with the cutoff lever) but I wasn't terribly impressed with the results sound-wise and the RoF seemed to have dropped. Today I went ahead and stripped the gearbox again, gave it a good clean and started with a thinner set of shims, and also used some new grease (Modify gear grease with Teflon). I tried my best to spend some time testing out each shim config as I went, testing for play and re-sealing the gearbox with each shim application.
I'm really pleased with the results, the sound, the responsiveness of trigger, and the improved RoF. Here's a video of me testing a 7.4V LiPo and a 9.6V NiMH battery with the updated gearbox:
JG G36 (Velocity Arms VA36) Testing After Shimming and Re-Grease - YouTube
You'll notice that my fire mode selector gets rattled around as the gun fires, which is not a new issue. I'm not sure how to fix this. If anyone has any suggestions, I'd love to hear them.