I'm building a hog rifle, 6.5 Grendel, as per recommendations from my last post, Proof Research carbon fiber barrel, Aero Precision BCG. Question, removing $$$ concerns, is there , above all others, a mil spec upper/lower that would be your first choice ?? Many thanks to all the gentlemen who took the time to answer my last post, very kind and appreciated, and many thanks for the upcoming opinions.