From what I understand it's a common complaint about LCT. The difference in QC between internal and external parts are polar opposites. It's one of the things which have make me hesitant to buy one as imo if I'm dropping that much on a new gun I expect it to work properly straight out of the box
It is indeed a common complaint. When I see a gun I like the look of, I research everything about it, including the quality of the internals and how easy, or otherwise, it is to work on. The only exception to this was my SLR, which I would have bought if it was a festering pile of poo internally, which it pretty much was until I did a lot of work on it.
The externals on his AKMS are superb and he has improved them by fitting rather battered genuine handguards. However, in addition to the spur gear issue, the gears were very poorly finished, being very sharp, and the pad on the cylinder head had fallen off. I decided to install an LCT QC gearbox that I had in the cupboard; after building it and installing new gears, it didn't fit properly. How can an LCT gearbox not fit an LCT gun?
However, after a lot of work and possibly one or two bad words, it is running nicely with the original gearbox.
He has had the AKMS for a few years now, getting it after I initially bought him an E&L, which was misaligned, with the barrel being canted to the left. Gunfire were far from helpful, so I contacted E&L, who were great; they arranged for me to return it to Gunfire and followed up with some freebies for us.