Birth of the AR-15

In 1948, the U.S. Army established the Operations Research Office (ORO) to analytically study a number of problems associated with ground weapons in the nuclear era.

One of ORO's early projects was ALCLAD, a search for better infantry body armor. During this search, the ORO discovered just how little was known about how individuals were wounded in combat. ORO looked into several questions regarding the manner in which soldiers were struck by rifle projectiles and shell fragments, including:

·         frequency and distribution of such hits

·         the types of wounds incurred in combat and

·         the average ranges at which wounds were inflicted

Answers to these questions were obtained by evaluating over three million casualty reports for World Wars I and II, as well as data from the Korean conflict.

ORO's investigations revealed that in the overall picture, aimed fire did not seem to have any more important role in creating casualties than randomly fired shots. Marksmanship was not as important as volume. Fire was seldom effectively used beyond 300 meters due to terrain (WWII, Korea) although sharpshooters in WWI frequently saw 1200m shots, and it discovered that most kills occur at 100 meters or less.

From this data, ORO concluded that what the Army needed was a low recoil weapon firing a number of small projectiles so in 1957 the United States Army Continental Army Command (CONARC) sought commercial assistance in the development of a 5.56mm military rifle.

CONARC sponsored the development of a .22 military rifle and asked Winchester and Armalite to come up with designs for a high-velocity, full and semi auto fire, 20 shot magazine, 6lbs loaded, able to penetrate both sides of a standard Army helmet at 500 meters rifle. The competing rifles were:

·         Winchester - .224 Lightweight Military Rifle - patterned after M1 and M1 Carbine

·         Springfield Armory - an Ordnance Corps facility, was forbidden to enter its rifle by those opposed to small caliber concept, but it too had a .224 model based on the M14

·         Armalite AR-15 -

The Armalite Division of the Fairchild Engine and Airplane Corporation, Costa Mesa, CA was established in 1954 for the sole purpose of developing military firearms using the latest in plastics and non-ferrous materials. It's team of Eugene M. Stoner - key designer, Robert Fremont - prototype manufacturing supervisor, and L. James Sullivan - who oversaw drafting work had been they key developers of the AR-15.

Prior to the AR-15, Armalite had developed:

AR-1 - 7.62 NATO parasniper rifle, extremely lightweight, using Mauser-type bolt action; only prototypes built in 1954

AR-3 - 7.62 NATO self-loader using aluminum receiver, fiberglass stock, and multiple lug locking system similar to the one later incorporated into the AR-10

AR-5 - .22 Hornet survival rifle developed for US Air Force and officially designated the MA-1

AR-7 - .22 long rifle self-loader, receiver and barrel store in plastic stock. (1959-1960)

AR-9 - 12 gauge self-loading shotgun with aluminum barrel and receiver (5lbs) 1955

AR-10 - 7.62 NATO auto-loader, aluminum receivers, led to AR-15 design

The AR-15, designed around slightly enlarged version of the .222 case firing a 55gr projectile at 3300fps, and weighing in at 6.7lbs, took some of the best features from earlier designs:

·         locking system similar to Johnson Automatic Rifle

·         gas system from Swedish Ljungman AG42B

·         in-line stock to help with manageability during auto fire

·         hinged upper/lower from FN-FAL

·         rear sight in carry handle like British EM2

·         ejector port cover from MP44

Project SALVO, a number of studies conducted by the Operations Research Office at Johns Hopkins University and supported by several contractors chose the AR-15 as the best small caliber weapon and it was adopted as the M16. The AR-15 had met all of the CONARC requirements, and AR-15 production could be highly automated, making it inexpensive to manufacture. It's 5.56mm cartridge fired a small 55gr bullet at nearly 3000fps, and it was accurate and effective to 350 yards. That small cartridge combined with the buffer system and inline stock made it far more controllable in automatic fire than the M14.

Evolution of the AR-15

In December of 1959, Colt acquired manufacturing and marketing rights to the AR-15. In 1962 Colt was able to get the Department of Defense's Advanced Research Project Agency (ARPA) to test 1,000 weapons in its Vietnam-oriented Project Agile. An enthusiastic report led to more studies from the Department of Defense and the Department of the Army, and despite strong Army opposition, Defense Secretary McNamara ordered 85,000 M16's for Vietnam, and 19,000 for the Air Force.

However, early reports showed that the M16 was not living up tp expectations. These reports, presented to McNamara by the Ordnance Department, showed the M16 having reliability as well as accuracy problems. These reports in turn praised the Ordnance Department's own M14. While the M14 performed well, it was too heavy for the hot jungles of Southeast Asia, and its ammunition also would not allow more than 50-100 rounds to be carried on patrols, severely limiting its capabilities as an automatic weapon.

Further evaluation of the M14 and M16 was done by an independent agency. It concluded that M14 was not as bad as had been suggested by some, that the AR-15 itself was not as good as its proponents had represented it to be. However, they did note that the AR-15 had greater capability for improvement, and that its small size and weight made it a handier weapon in Vietnam.

The M16 was issued w/o proper training and inadequate cleaning supplies. Combined with the humid jungle of Southeast Asia, this caused problems and the rifle gained a bad reputation. Because tolerances were tighter than in previous military arms, the M16 had to be kept extremely clean. War correspondents filed reports where the M16 was jamming, and many were shown on the evening news. It was reported that our soldiers were being killed by a faulty rifle.

This led to Congressional investigations which turned up two related problems. First, the cleaning issue. As training was provided, supplies issued, and some redesign, M16 performed more reliably. The second issue dealt with the use of ball propellants instead of IMR propellants. Remington had developed the 5.56mm round using one type of powder, but the specification was changed during military contract production to allow an alternate. This powder caused more fouling and increased the rate of fire.

M16A1
The replacement of the powder, combined with a new buffer to slow rate of fire, a chrome plated chamber and barrel to improve rust resistance, a closed prong flash-hider, forward bolt assist, new buttstock w/storage for cleaning kit, and introduction of a 30-shot magazine was adopted as the M16A1 and performed well for the duration of the 60's and 70's. This rifle was also produced by GM and Harington & Richardson during Vietnam era as well as other countries including the Philippines.

M16A2
In the late 1970's, the Army re-examined it's rifle situation. Existing M16s were well worn, and the current programs that were looking into a replacement for the M16 were not far enough along. So in 1978, the M16 underwent a Product Improvement Program.

The results were an increased barrel diameter, and one whose rifling was changed from 1:12 to 1:7 to accomodate the new round, developed by Belgium's Fabrique Nationale, the SS109. This round extended the range of the rifle, and propelled a 62gr bullet with a steel core at over 3000 fps. The rear sight was modified to allow more accurate adjustments of windage by hand, as well as for elevation calibrated out to 800 meters. It incorporated a case deflector to prevent brass from hitting left-handed firers, and new round handguards to replace the older triangular design. Also, full-auto capability was replaced with a three-shot burst. This allowed for more controlled firing, as well as greater accuracy as all three rounds are downrange before the effects of recoil can impact their path. This new rifle was adopted as the M16A2.

M4
In 1994, the U.S. Army officially adopted its second carbine of the 20th century. Though carbine versions of the M16 had been used all along (as the XM177 as well as the CAR-15), demand for these was limited to select groups. With the increase in the use of Special Operations forces during and after the Cold War, the demand for a shorter, lightweight weapon was increased.

The M4 was developed by Colt's Manufacturing Company, and is intended to be used by Special Operations forces as well as other select members of the military. It is designed to replace a variety of carbines and SMGs in the Army's arsenal, as well as to repeat the accuracy and reliability of the M16A2. It uses a 14.5" barrel, and a four-position telescoping stock while maintaining the ability to mount an M203 grenade launcher. In the collapsed position, it measures under 30 inches, and weights just over 5 1/2 pounds, with an effective range of 600 meters. The M4 is available with 3-shot bursts (M4) as well as full-auto capabilities (M4A1).

Both versions of the M4 are equipped with a Picatinny-Weaver Rail system to replace the carry handle. This allows for a variety of sighting systems to be mounted atop the receiver, from the standard handle with A2 sights to night-vision devices, scopes, and lasers.