RE: M-16 guaranteed MOA is....
While attending Colt M-16 Armorer's school, we were told that that the barrel life of these guns was 35,000 to 70,000 rounds. The guns would normally hold a 5 MOA group up to that level of barrel wear. I wasn't sure I heard right for a moment . . . . . . Normally, my guns are looking for new barrel when the groups open up to MOA - normally about 5,000 rounds on a premium .223 barrel.