Pwm1830
so... realistically, can an AR platform do .5MOA.. yep... but very likely not all day long. not if you are talking ES measurement that the internet likes. Now if you are talking ATC or some other measurement that allows for statistical flyers they yes.. .5 all day long might be more achievable
many good and even average mfg can make the AR platform that will turn in the occaisional 3 or even 5 round group that will be sub .5MOA but I have yet to see one in my lifetime turn in a 10 round group under .5 let alone multiple 10 round groups overlayed for a 30 round composit.. never seen it.. maybe Molon has .. as that man is an AR god.. but I have never seen him shoot a 30 round composit that is .5 either come to think of it.
different animal but when the military was looking at the M110 trials the initial requiremnt for for a 1MOA max.. they had to relax that to 1.5 and these where hand built test guns from top tier defense contractors like remington and Knights competing and they all asked for the requirement to be relaxed.. why.. becuase the govt doesnt cherry pick groups.. those guns that go through testing at aberdeen prooving grounds for contracts have to meet the milspec ALL DAY LONG.. shoot one group outside the maximum specified and you are out.
here is another dirty secret of the AR platform.. any rounds chambered from a bolt open condition like a mag change or a malf clearing will almost always shoot out of the group becase the bolt lockup is far more violent from a recoil rebound than from the bolt release. moreover.. depending on the hand lapping of the bolt to extension interface.. many when single loaded will group far worse than a string fired from the magzine... when firing in a match or for groups where its allowed a shooter will throw that first shot into the ground and not the target.
conversly .. especially in the ar-10 .. if you loads dont have LOTS of neck tension.. the round will grow measureably when chambered.. I have seen rounds chambered than ejected that would no longer fit the magazine having set the bullet forward enough to see with the naked eye. this is exacerbated in rounds that chamber from recoil and not bolt release.
in sum.. the AR platform can attain resonable accuracy but if you were trying to build one that would never throw a round outside .5 .. I would say its a fools errand at any cost... hence the reason we still have bolt guns and when a shot has to mater, when a hostages head and a perps head are within inches of one another, nobody is taking that shot with a semi..