An extract on #balitravel
After World War II, the United States military started looking for a single automatic rifle to replace the M1 Garand, M1/M2 Carbines, M1918 Browning Automatic Rifle, M3 "Grease Gun" and Thompson submachine gun. However, early experiments with select-fire versions of the M1 Garand proved disappointing. During the Korean War, the select-fire M2 carbine largely replaced the submachine gun in US service and became the most widely used Carbine variant. However, combat experience suggested that the .30 Carbine round was under-powered. American weapons designers concluded that an intermediate round was necessary, and recommended a small-caliber, high-velocity cartridge.
However, senior American commanders having faced fanatical enemies and experienced major logistical problems during WWII and the Korean War, insisted that a single powerful .30 caliber cartridge be developed, that could not only be used by the new automatic rifle, but by the new general-purpose machine gun (GPMG) in concurrent development. This culminated in the development of the 7.6251mm NATO cartridge.
The United States Army then began testing several rifles to replace the obsolete M1 Garand. Springfield Armory's T44E4 and heavier T44E5 were essentially updated versions of the Garand chambered for the new 7.62 mm round, while Fabrique Nationale submitted their FN FAL as the T48. ArmaLite entered the competition late, hurriedly submitting several AR-10 prototype rifles in the fall of 1956 to the United States Army's Springfield Armory for testing.
The AR-10 featured an innovative straight-line barrel/stock design, forged aluminum alloy receivers and with phenolic composite stocks. It had rugged elevated sights, an oversized aluminum flash suppressor and recoil compensator, and an adjustable gas system. The final prototype, featured an upper and lower receiver with the now-familiar hinge and takedown pins, and the charging handle was on top of the receiver placed inside of the carry handle. For a 7.62mm NATO rifle, the AR-10 was incredibly lightweight at only 6.85 lbs. empty. Initial comments by Springfield Armory test staff were favorable, and some testers commented that the AR-10 was the best lightweight automatic rifle ever tested by the Armory.
In the end the United States Army chose the T44 now called the M14 rifle which was an improved M1 Garand with a 20-round magazine and automatic fire capability. The U.S. also adopted the M60 general purpose machine gun (GPMG). Its NATO partners adopted the FN FAL and HK G3 rifles, as well as the FN MAG and Rheinmetall MG3 GPMGs.
The first confrontations between the AK-47 and the M14 came in the early part of the Vietnam War. Battlefield reports indicated that the M14 was uncontrollable in full-auto and that soldiers could not carry enough ammo to maintain fire superiority over the AK-47. And, while the M2 carbine offered a high rate of fire, it was under-powered and ultimately outclassed by the AK-47. A replacement was needed: a medium between the traditional preference for high-powered rifles such as the M14, and the lightweight firepower of the M2 Carbine.
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 caliber (5.56mm) select-fire rifle weighing 6 lb (2.7 kg) when loaded with a 20-round magazine. The 5.56mm 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.
This request ultimately resulted in the development of a scaled-down version of the Armalite AR-10, called ArmaLite AR-15 rifle. 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. At the time, the AR-15 was the only rifle available that could fulfill the requirement of a universal infantry weapon for issue to all services.
After modifications (most notably, the charging handle was re-located from under the carrying handle like AR-10 to the rear of the receiver), the new redesigned rifle was subsequently adopted as the M16 Rifle and went into production in March 1964. "(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."