The M16 rifle is a family of military rifles adapted from the ArmaLite AR-15 rifle for the United States military. The original M16 rifle was a 5.56×45mm automatic rifle with a 20-round magazine.
M16A2, multi-sided view
From top to bottom: M16A1, M16A2, M4A1, M16A4
A Marine of the 3rd Battalion, 1st Marines cleans his XM16E1 in December 1967
Front cover – The M16A1 Rifle – Operation and Preventive Maintenance by Will Eisner, issued to American soldiers in the Vietnam War.
The ArmaLite AR-15 is a select-fire, gas-operated, air-cooled, magazine-fed rifle manufactured in the United States between 1959 and 1964. Designed by American gun manufacturer ArmaLite in 1956, it was based on its AR-10 rifle. The ArmaLite AR-15 was designed to be a lightweight rifle and to fire a new high-velocity, lightweight, small-caliber cartridge to allow infantrymen to carry more ammunition.
ArmaLite AR-10 made by Artillerie Inrichtingen (A.I.)
Colt ArmaLite AR-15 Model 01 with 20-round magazine
Colt ArmaLite AR-15 Model 02 without magazine and new 1 in 12-inch (300 mm) rifling twist rate
An early M16 rifle without forward assist