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 ArmaLite AR-10 featured an innovative combination of a straight-line barrel/stock design, a new patent-filed gas-operated bolt, forged aluminum alloy receivers and with phenolic composite stocks resulting in a small arm significantly easier to control in automatic fire than other infantry rifles of the day. 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 1950s 7.62×51mm NATO rifle, the AR-10 was incredibly lightweight at only 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, which entered service as 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, and 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. 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. Scaling down the ArmaLite AR-10 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 (5.56 mm) 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. M1 helmet at and retain a velocity in excess of the speed of sound, while matching or exceeding the wounding ability of the