@Glennn,
You mean other than the US Army thought it was when they adopted it?
As a result, the Army was forced to reconsider a 1957 request by General Willard G. Wyman, commander of the U.S. Continental Army Command (CONARC) to develop a .223 inch caliber (5.56 mm) select-fire rifle weighing 6 lb (2.7 kg) when loaded with a 20-round magazine.[27] The 5.56 mm round had to penetrate a standard U.S. helmet at 500 yards (460 meters) and retain a velocity in excess of the speed of sound, while matching or exceeding the wounding ability of the .30 Carbine cartridge.[51]
This request ultimately resulted in the development of a scaled-down version of the Armalite AR-10, named ArmaLite AR-15 rifle.[52][53][54] In the late 1950s, designer Eugene Stoner was completing his work on the AR-15. The AR-15 used .22-caliber bullets, which destabilized when they hit a human body, as opposed to the .30 round, which typically passed through in a straight line. The smaller caliber meant that it could be controlled in autofire due the reduced recoil. Being almost one-third the weight of the .30 meant that the soldier could sustain fire for longer with the same load. Due to design innovations, the AR-15 could fire 600 to 700 rounds a minute with an extremely low jamming rate. Parts were stamped out, not hand-machined, so could be mass-produced, and the stock was plastic to reduce weight.[26]
ArmaLite AR-15
In 1958, the Army's Combat Developments Experimentation Command ran experiments with small squads in combat situations using the M14, AR-15, and another rifle designed by Winchester. The resulting study recommended adopting a lightweight rifle like the AR-15. In response, the Army declared that all rifles and machine guns should use the same ammunition, and ordered full production of the M-14.[26] However, advocates for the AR-15 gained the attention of Air Force Chief of Staff General Curtis Lemay. After testing the AR-15 with the ammunition manufactured by Remington that Armalite and Colt recommended, the Air Force declared that the AR-15 was its 'standard model' and ordered 8,500 rifles and 8.5 million rounds.[26] Advocates for the AR-15 in the Defense Advanced Research Projects Agency acquired 1,000 Air Force AR-15s and shipped them to be tested by the Army of the Republic of Vietnam (ARVN). The South Vietnam soldiers issued glowing reports of the weapon's reliability, recording zero broken parts while firing 80,000 rounds in one stage of testing, and requiring only two replacement parts for the 1,000 weapons over the entire course of testing. The report of the experiment recommended that the U.S. provide the AR-15 as the standard rifle of the ARVN, but Admiral Harry Felt, then Commander in Chief, Pacific Forces, rejected the recommendations on the advice of the U.S. Army.[26]
Throughout 1962 and 1963, the U.S. military extensively tested the AR-15. Positive evaluations emphasized its lightness, "lethality", and reliability.[26] However, the Army Materiel Command criticized its inaccuracy at longer ranges and lack of penetrating power at higher ranges.[52][46][26] In early 1963, the U.S. Special Forces asked, and was given permission, to make the AR-15 its standard weapon. Other users included Army Airborne units in Vietnam and some units affiliated with the Central Intelligence Agency. As more units adopted the AR-15, Secretary of the Army Cyrus Vance ordered an investigation into why the weapon had been rejected by the Army. The resulting report found that Army Materiel Command had rigged the previous tests, selecting tests that would favor the M14 and choosing match grade M14s to compete against AR-15s out of the box.[26] At this point, the bureaucratic battle lines were well-defined, with the Army ordnance agencies opposed to the AR-15 and the Air Force and civilian leadership of the Defense Department in favor.[26]
In January 1963, Secretary of Defense Robert McNamara concluded that the AR-15 was the superior weapon system and ordered a halt to M14 production.[52][46] In late 1963, the Defense Department began mass procurement of rifles for the Air Force and special Army units. Secretary McNamara designated the Army as the procurer for the weapon with the Department, which allowed the Army ordnance establishment to modify the weapon as they wished. The first modification was the additions of a "manual bolt closure," allowing a soldier to ram in a round if it failed to seat properly. The Air Force, which was buying the rifle, and the Marine Corps, which had tested it both objected to this addition, with the Air Force noting, "During three years of testing and operation of the AR-15 rifle under all types of conditions the Air Force has no record of malfunctions that could have been corrected by a manual bolt closing device." They also noted that the closure added weight and complexity, reducing the reliability of the weapon. Colonel Howard Yount, who managed the Army procurement, would later state the bolt closure was added after direction from senior leadership, rather than as a result of any complaint or test result, and testified about the reasons: "the M-1, the M-14, and the carbine had always had something for the soldier to push on; that maybe this would be a comforting feeling to him, or something."[26][55]
After modifications,[53] the new redesigned rifle was subsequently adopted as the M16 Rifle.[1][52][46] "(The M16) was much lighter compared to the M14 it replaced, ultimately allowing soldiers to carry more ammunition. The air-cooled, gas-operated, magazine-fed assault rifle was made of steel, aluminum alloy and composite plastics, truly cutting-edge for the time. Designed with full and semi-automatic capabilities, the weapon initially did not respond well to wet and dirty conditions, sometimes even jamming in combat. After a few minor modifications, the weapon gained in popularity among troops on the battlefield."[46][56][57]
An M16A1
Despite its early failures the M16 proved to be a revolutionary design and stands as the longest continuously serving rifle in US military history.[1][52] It has been adopted by many US allies and the 5.56×45mm NATO cartridge has become not only the NATO standard, but "the standard assault-rifle cartridge in much of the world."[52][58][59] It also led to the development of small-caliber high-velocity service rifles by every major army in the world.[52] It is a benchmark against which other assault rifles are judged.[52][60][61]
M16s were produced by Colt until the late 1980s, when FN Herstal began to manufacture them.[62]
Adoption
In July 1960, General Curtis LeMay was impressed by a demonstration of the ArmaLite AR-15. In the summer of 1961, General LeMay was promoted to U.S. Air Force, Chief of Staff, and requested 80,000 AR-15s. However, General Maxwell D. Taylor, Chairman of the Joint Chiefs of Staff, advised President John F. Kennedy that having two different calibers within the military system at the same time would be problematic and the request was rejected.[63] In October 1961, William Godel, a senior man at the Advanced Research Projects Agency, sent 10 AR-15s to South Vietnam. The reception was enthusiastic, and in 1962 another 1,000 AR-15s were sent.[64] United States Army Special Forces personnel filed battlefield reports lavishly praising the AR-15 and the stopping-power of the 5.56 mm cartridge, and pressed for its adoption.[46]
The damage caused by the 5.56 mm bullet was originally believed to be caused by "tumbling" due to the slow 1 turn in 14-inch (360 mm) rifling twist rate.[46][63] However, any pointed lead core bullet will "tumble" after penetration in flesh, because the center of gravity is towards the rear of the bullet. The large wounds observed by soldiers in Vietnam were actually caused by bullet fragmentation created by a combination of the bullet's velocity and construction.[65] These wounds were so devastating, that the photographs remained classified into the 1980s.[66]
However, despite overwhelming evidence that the AR-15 could bring more firepower to bear than the M14, the Army opposed the adoption of the new rifle.[52][46] U.S. Secretary of Defense Robert McNamara now had two conflicting views: the ARPA report[67] favoring the AR-15 and the Army's position favoring the M14.[46] Even President Kennedy expressed concern, so McNamara ordered Secretary of the Army Cyrus Vance to test the M14, the AR-15 and the AK-47. The Army reported that only the M14 was suitable for service, but Vance wondered about the impartiality of those conducting the tests. He ordered the Army Inspector General to investigate the testing methods used; the Inspector General confirmed that the testers were biased towards the M14.
In January 1963, Secretary McNamara received reports that M14 production was insufficient to meet the needs of the armed forces and ordered a halt to M14 production.[46] At the time, the AR-15 was the only rifle that could fulfill a requirement of a "universal" infantry weapon for issue to all services. McNamara ordered its adoption, despite receiving reports of several deficiencies, most notably the lack of a chrome-plated chamber.[68][1]
101st Airborne trooper cleans his XM16E1 during the Vietnam War in 1966
Front cover – The M16A1 Rifle – Operation and Preventive Maintenance by Will Eisner
After modifications (most notably, the charging handle was re-located from under the carrying handle like AR-10 to the rear of the receiver),[53] the new redesigned rifle was renamed the Rifle, Caliber 5.56 mm, M16.[1][52] Inexplicably, the modification to the new M16 did not include a chrome-plated barrel. Meanwhile, the Army relented and recommended the adoption of the M16 for jungle warfare operations. However, the Army insisted on the inclusion of a forward assist to help push the bolt into battery in the event that a cartridge failed to seat into the chamber. The Air Force, Colt and Eugene Stoner believed that the addition of a forward assist was an unjustified expense. As a result, the design was split into two variants: the Air Force's M16 without the forward assist, and the XM16E1 with the forward assist for the other service branches.
In November 1963, McNamara approved the U.S. Army's order of 85,000 XM16E1s;[46][69] and to appease General LeMay, the Air Force was granted an order for another 19,000 M16s.[70][71] In March 1964, the M16 rifle went into production and the Army accepted delivery of the first batch of 2,129 rifles later that year, and an additional 57,240 rifles the following year.[1]
In 1964, the Army was informed that DuPont could not mass-produce the IMR 4475 stick powder to the specifications demanded by the M16. Therefore, Olin Mathieson Company provided a high-performance ball propellant. While the Olin WC 846 powder achieved the desired 3,300 ft (1,000 m) per second muzzle velocity, it produced much more fouling, that quickly jammed the M16s action (unless the rifle was cleaned well and often).
