I was talking to a buddy that shoots a lot of hi-power service rifle competitions (actually he's ranked in the top 15 in the nation), anyway, he was saying that the last few Rock River uppers he has bought all had problems. Either the bolt was sloppy, sights were messed up, accuracy was poor, something with every one.
I'm suprised that he buys production uppers instaed of something semi-custom like a WHite Oak Armaments of Compass Lake Engineering upper. Production rifles are put together with parts from a parts bin, some custom manufacturers like the ones listed above carefully handfit the uppers together from custom made parts. If he's a top notch shooter he will notice the flaws in something in a RRA that most people won't- especially with sight repeatabilityand sight adjustment accuracy (if whether or not the sights adjust in 1/4 or 1/2 moa adjustments like their supposed to or actually end up something like 3/8 ,5/8 MOA adjustments).