M-16 5.56mm Rifle History

Rifle, 5.56mm, M-16A1.

In 1962, early in the Vietnam War, Colt brought the Armalite AR-15 to the Advanced Research Projects Agency (ARPA, now DARPA). Impressed, ARPA sponsored a combat demonstration of the AR-15 in Vietnam. The AR-15 was chambered for the .223 cal. (5.56 mm) cartridge, far smaller than the then standard 7.62 NATO round or the classic .30-06 but promoted as just as lethal due to its high velocity and tumbling on impact.

According to a report on the matter by the SFTT website:

In October 1961, ARPA provided ten Colt AR-15s to Vietnamese Forces in Saigon to conduct a limited test. The Black Rifle remarks of this test, "The number of rifles might have been small, but the enthusiastic reaction of the Vietnamese and their American advisors alike who handled and fired the AR-15s was just as [Colt's marketing agent] had predicted." Armed with these positive results, ARPA succeeded in expanding the Project AGILE study by procuring 1,000 AR-15s for distribution among select Vietnamese units for field testing. Ezell and Stevens wrote that this approval resulted in "... saving Colt's from almost sure financial disaster and also setting the stage for the most influential yet controversial document so far in the history of the already controversial AR-15."

The AGILE report enthusiasticly supported the AR-15 as "...superior in virtually all respects to the M-1 Rifle, M-1 and M-2 Carbines, Thompson Sub-Machine Gun, and Browning Automatic Rifle." However, this statement was specifically related to equipping the Vietnamese who were small in stature compared to typical US soldiers. Further testing failed to reproduce the lethality claimed by the original report for the 5.56 ammunition.

Even though the AR-15 report and tests of the .223 ammunition were controversial, in 1963 the US Army began purchasing the M16 for use in Vietnam where it was issued to Sepcial Forces. The Army ordered 85,000 rifles in 1963, 35,000 more in 1964, 100,000 in 1965, and 100,000 in 1966. At first they were issued to Special Forces, Airborne, helicopter crews, Air Commando and other special category troops in Vietnam as well as forces in the Dominican Republic.

In 1965 the M-16 became the military's basic service rifle and was in widespread use by 1966. Troops generally liked the light weight rifle and the ability to carry more ammo, but complained about insufficient range and lethality. Despite Colt's claims that it was maintenance free, there were early problems due to poor maintenance training, and to the jungle climate of Southeast Asia. It has also been claimed that a change in the 5.56 ammo propellant caused fouling until chrome plating was introduced to offset the problem.

Through 2003, the total quantity produced in all models world-wide was about 7 million.

M-16 Rifle Characteristics

Rifle, 5.56mm, M-16A2.

The M-16 is selectable for full and automatic fire. The M16 was to have had the same effective range as the M-14 rifle it replaced, but it was most effective at a range of 215 yards (200m) or less. The M-16 used a 5.56mm (.223 cal.) cartridge in 20- or 30-round magazines.

The M-16A2 was introduced in 1982 with improvements over the M-16 and M-16A1. The M-16A2 is equipped with a burst control device so that each pull of the trigger fires one shot if single shots are selected. In automatic fire, the M-16A2 automatically fires a three-shot burst for each trigger-pull, considered optimum from Army research. The M-16A2 also incorporates a more durable plastic handguard, rifle stock, and pistol grip, interchangeable handguard halves, an adjustable dual-aperture rear sight that corrects for both windage and elevation, a heavier barrel to increase accuracy, 1-in-7 rifling, a brass deflector to prevent ejected casings from hitting left-handed shooters, and an effective muzzle compensator to prevent muzzle climb during auto fire.

The M16A4 rifle is a modified M16A2 service rifle. An M1913 Rail Adapter System (RAS) replaces the upper hand guards of the M16A2 and incorporates a removable rear-carrying handle. The rail adapter system and modified hand guards allow for the mounting of various accessories such as a modified M203 launching system, high intensity flashlights, and IR laser target designators as well as optics.

In 2003 the U.S. Army issued limited numbers of the M-16A3 and M-16A4, which incorporate a rail mounting system similar to the M-4A1 Carbine. The M4 Carbine, a shortened version of the M-16A2 is replacing the longer standard rifle in selected military units.

M-16 Rifle Bayonets

The M-16 Rifle uses the M-7 bayonet which was replaced by the newer M-9 Multipurpose Bayonet System starting in 1987. Since 2002, Marines use the USMC Multipurpose Bayonet (MB). The M-4 Carbine is interchangable with the M-16 for these bayonets.

Commercial Sources of the AR-15/M-16 Rifle

The world wide popularity of the M16 family of rifles has created a demand for the firearms, parts, and accessories. As of 2008, these companies supply the largest numbers of rifles for the military, law enforcement, and civilian markets:

Opinions about the quality and value of the various manufacturers is hotly debated, so be sure to check in with forums (AR15.com in particular) for the latest news and advice.

Recommended Books about the M-16 5.56mm Rifle

Find More Information on the Web

There are many fine websites that have additional information on this topic, too many to list here and too many to keep up with as they come and go. Use this Google web search form to get an up to date report of what's out there.

For good results, try entering this: m16 or m16a1 or m15a2 or ar-15. Then click the Search button.