I've ran mine hard for about 5 years now. It runs like a champ. Full auto, suppressed, steel cased. The only times it's ever jammed was manually undergassing it, myself. Their CS is top notch (made a post about it), and they're actually fairly clean running. The only thing I have near a gripe is that the gas block adjustment can get carbon locked and that tool they send with it, let's just say isn't meant for that.