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The M16A2. After two decades of service, the M16A2 replaced the M16A1. The differences between the two weapons effectively converted the M16A2 into a more traditional military rifle. This fit the Marine Corps vision of a general issue rifle. In a nutshell, the M16A2 had an increased rifle twist for a new 5.56 NATO cartridge, a lengthened butt stock, finger grove pistol grip, three shot burst control replacing the full auto capability, a redesigned rear sight which increased the range graduations to 800 meters, an improved flash suppressor, and a heavier barrel which gave the rifle improved balance in the offhand shooting position.
M16A2 fired offhand
While these “improvements” were great for target shooters, a lot of the handling characteristics of the assault rifle were lost. The Army was warned about the M16A2 and its 5.56 caliber Ball M855 ammunition by a report prepared by the Army Research Institute Field unit located at Fort Benning, Georgia. The M16A2 rifle was now longer and heavier, well suited for the National Match Course and other target shooting competitions. Its sighting system was redesigned to provide settings for distances up to 800 meters. The intent of the assault rifle, the ability to reliably hit enemy soldiers at ranges of 300 meters and less, was lost. The 3 shot burst was in response to the old full auto, and presumably soldiers, waste ammunition argument.
Another unhappy coincidence was the widespread use of kevlar body armor by U.S. troops in the late 1990s. While in the vests, many smaller stature soldiers could not effectively sight their longer stocked M16A2 rifles. The M16A2 is outstandingly accurate, very reliable, and provided good service to U.S. troops in Panama, Desert Storm, and in the early stages of the Global War on Terror. In the end, it really turned out to be a heavy, intermediate cartridge, battle rifle, designed to hit targets well beyond the effective range of its “improved” cartridge.