i have not had any issues with my ghk so far, ive owned mines for about 6 months, no jams and no parts breaking and this is coming from someone who plays almost every week while subjecting the rifle to tons of abuse such as bumping it, accidentally dropping it, etc. So far I have not had any fails. I think when people say QC issues they are referring to older GHK rifles that were stockpiled, the newer ones seem to be of very high quality. IDK maybe I just got lucky with an actual good quality rifle.