In the early 1950’s the United States Army’s Operation Research Office (ORO) concluded that the preferred infantry small arms should be .22 caliber, offer select fire, use high velocity bullets and be effective up to approximately three hundred meters. In the late 1950’s the United States Department of Defense (DOD) “Project Salvo” also concludes that a .22 caliber high velocity rifle is the best choice for infantry. The United States Army then asks Armalite to develop a lightweight, .22 caliber, select fire rifle capable of piercing a standard steel helmet from five hundred yards. The M16A2 was introduced as the United States Military weapon of choice in the 1980’s. The M16 rifle series has been used since the 1960’s. It began being used in the Army in 1964 as a limited standard rifle to fill the void between the discontinued 7.62mm M14 rifle and the forthcoming Special Purpose Individual Weapon (SPIW) system which never came to fruition having been unable to get past the prototype and trial stages. The M16 was designed by Eugene Stoner who at the time was employed by Armalite. The rifles were modeled after the ArmaLite AR15, the civilian equivalent of the M16. The M16 rifle series includes the A1, A2, A3, and A4. The M16A2 was designed to fire the standard NATO cartridge, the M885/M886 cartridge designed by the Belgians. The M16A1 was used until the 1980’s when the US military adopted the M16A2. The M16A3 is a variation of the M16A2 used only by the United States Navy and the M16A4 was introduced as the primary issue weapon for the United States Marine Corps in Operation Iraqi Freedom. The United States Army is using a combination of weapons in the current conflicts, the M16A2, the M16A4 and the M4 carbine. The M16 rifle is primarily manufactured by Colt and Fabrique Nationale de Herstal. The M16A2 is a 5.56 millimeter caliber, magazine fed, gas operated, air cooled, hand held, shoulder or hip fired weapon. It has both automatic and semiautomatic...