They were called the ABCs: Armalite, Bushmaster, and Colt. Colt was looked down upon because of the non-standard takedown pins and the internal "fence" that prevented, IIRC, the use of an M16 BCG.
Both Armalite and Bushmaster made fine products in those days as did Colt but folks didn't like Colt's politics, so to speak. Way down the list was Olympia and especially Spirit. Spirit had a particularly odious owner named Bob Reisner and no CS.
Ahh, those were the days.