Impressive to say the least, I don't know how many rounds were fired today through the 10.5 416 upper but it was a good mix of at least 300-500 rounds of RUAG, and a couple of hundred Wolf .223,and some mixed bag rounds. When I popped it open at the end of the day the bolt was still lubed and fairly clean.Even the carbon hidey holes such as the ejection port cover spring was clean.
Definitely was drinking the HK Kool Aide today, and loved every min of it,if I had the disposable income I would get one for sure,as I abuse the hell out of my AR's , my Colt LE Carbine has not seen cleaning since 2006,just moly grease for lube every now and then it still runs like a champ. The HK system is about the top of the heap of the AR FOW, gas gun or piston, one day I will ahve one, but will not be dropping the DI system just yet. In Afghanistan or Iraq... different story if one was available I'd snap it up.