Military Standard of a 5-inch group with iron sights at 100 yards
5 MOA with Iron sights using military spec M855.
I would actually call that pretty respectable. Shooting that with a magnified optic using match grade ammo, wouldn't be very good.
The spec for the M-14 was 8 MOA with M80 Ball which doesn't have a seperate steel penetrator that can be assembled out of the centerline of the bullet and cause wobble.
It is true however, if you want a super accurate gun, Colt 6920 ISN'T the way to go. (No combat rifle is)
Something with a high quality stainless or standard chrome-moly free float barrel with give much better accuracy and if you are chiefly worried about accuracy and not so much reliability, a nice tight .223 Remington chamber and staying with match rounds will help alot.
Thanks for the link.
As I said, most of the 6920s i've shot are around 2.5 MOA with an optic and good ammo, which is well within combat standards. Also remember, the guy testing to see if their accuracy is "milspec" is very proficient with iron sights. Personally, with standard ar-15 sights and a very accurate ar-15 and good ammo, i can get 1.5 MOA every time, and 1 MOA 75% of the time since for the first 4 years shooting ARs I only used Irons, and I probably put 25k+ rounds downrange with them. Imagine what the guy that shoots ar-15s with irons from 9 to 5 every day
I believe almost every gun serves a purpose, and the colt serves a very good purpose as a combat rifle, but as a "range gun" it lacks some of the features that one would like, like the m4 profile barrel, it's almost useless on a "range gun" unless you plan on mounting a m203 on it. Or 7075 T6 Forged parts, I doubt that the OP will need the benefits of those parts.
By no means was I saying that the 6920 was a bad gun, I was just saying that it fills a need that most civilians doesn't have.