I'm no expert on the subject by any means but I have noticed the same thing. I wonder if most of the forged lowers come from the same plant and are finished machined and anodized by Bushmaster, Armalite, whoever. I've got Stag, Eagle/Armalite, Oly and even a Sendra I traded a bayonet for years ago. They are all forged and pretty much the same. I doubt all of the AR companies are big enough to own their forging equipment. I've never had a problem with any of my lowers being machined out of tolerance. I've bought uppers from ADCO, RRA, WOA, etc. and they are all pretty much the same. I did see some A2 uppers once that looked like the makers forge marks were ground off and then the whole thing anodized again. They looked like crap. They came from Nesard and Sun Valley if I remember right. That was years ago. I'm not sure if anyone sells these reject parts anymore. Everything I've bought from WOA, RRA, RB, Eagle, ADCO, Bushmaster and Del-Ton has been great stuff. I doubt there is 10 cents difference between a $100 CMT and a $120 Bushmaster. Can't go wrong either way.