Early Service
In 1962, the U.S. Air Force adopted the AR-15 as the M16 rifle. Shortly afterward, the U.S. Army also adopted it, designating it as the XM16E1. The rifle went through several improvements and refinements, and by 1967, the M16A1 was officially standardized as the U.S. Army's primary infantry rifle.
The M16A1 featured a 20-inch barrel, a forward-assist to ensure proper bolt closure, and a flash suppressor. It was capable of both semi-automatic and fully automatic fire modes, enhancing its versatility in combat. One of its defining characteristics was the ability to use a detachable magazine, initially holding 20 rounds but later increasing to 30 rounds.