Quick question regarding a 6.5 build. Everything I've read has led me to believe a 6.5 upper can be build with standard AR-15 parts with the exception of the bolt and the barrel.
Then I ran across this
One cannot simply slap a 6.5mm barrel on any AR-15 and achieve a high level of competitive accuracy. The Alexander Arms Grendel rifles use Lothar Walther hand-lapped stainless barrels that are carefully chambered, throated, crowned, and fitted to the upper receiver. Even the throat is specially cut and lapped for increased accuracy. The upper and lower receivers are precisely fitted, with absolutely no play between the halves.
Is this just the standard marketing junk? Can I still, in fact, install a Grendel barrel onto a standard A3 upper? Can I then stick that upper on my existing lower?