[Guns] What does accuracy represent?

[MrFix]

Originally Posted by solidsingularity

Where did you find that?

Ugh, I had the article open for like 2 weeks and when I finally closed it, you ask about it. I'll search around for it and add the link in an edit.

The gist of the article was that in the early 2000s as part of a program to replace M249, a bunch of firearms were gathered from the competitors as potential replacement, including the H&K G36 (Not MG36), Ultimax 100 and Colt AR. They gathered new marines and had them fire each of the weapon across numerous courses. The end result was that M249 behaved similarly, or better than G36 in accuracy department. The internet reports that G36 has MOA of 1.5-3.

Other forum posts suggested that their M249 was accurate enough (the 6 MOA number). Noveske also makes AR-15 barrels using M249 specs, which end up performing within 1-1.5 MOA. This data suggests to me that M249 is at best only slightly less accurate than M16 and G36, and this is probably owed to it's open bolt design.

Edit: Marine Corps Magazine: Automatic Rifle Concept: Part I—History and Empirical Testing
Forum topic of AR-15 users speaking about their experience with Noveske M249-pattern AR15 barrel

The M249 SAW provides the accuracy that fire teams and squads require. The quantitative tests of Phase I proved the variation in accuracy between the M249 SAW and its competitors small enough to not be worth the time, money, and effort to replace it. Despite the mitigation of the accuracy issue, the M249 SAW could not meet the requirements of mobility and semiautomatic fire accuracy.
Unfortunately, the competitors tested during Phase I of the AR assessment do not appear to offer what the Marine Corps needs. As stated previously, the HK failed to stay on target in burst fire while the Ultimax sight system did not present to the eye at all. The commonality of the Colt AR with the M16A2 appeared to be advantageous. Yet the Colt proved to be the only weapon that experienced negligent discharges during the firing of 120,000 rounds. This fault resulted, in part, from young Marines failing to understand the open-bolt system but also, in part, from weapon design. Open bolts are inherently dangerous. Traditionally, we fear carrying an open-bolt weapon in the condition one mode of ready to fire. The primary shooter can be trained to be safe with the weapon, but primary shooter casualties will soon place the weapons in untrained hands, quickly leading to friendly fire hazards.

Phase I testing did not provide a “yes” to the original question—“is an AR more accurate than the M249 SAW?” It did, however, highlight the need for a mobile AR, capable of semiautomatic fire at the fire team level. Further, it illuminated the need to address the future employment and role of the M249 SAW light machinegun and a “true” AR in the fire teams, squads, and platoons of the Marine Corps.