M16 rifle

The M16 rifle, officially designated Rifle, Caliber 5.56 mm, M16, 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 mm assault rifle with a 20-round magazine.

Rifle, Caliber 5.56 mm, M16
M16A2, multi-sided view
TypeAssault rifle
Place of originUnited States
Service history
In service1964–present[1]
Used bySee Users
WarsSee Conflicts
Production history
DesignerEugene Stoner (AR-10)[2]
L. James Sullivan (AR-15)[3]
  • 1963–present[1]
No. builtc. 8 million as of 2011[1]
VariantsSee List of Colt AR-15 and M16 rifle variants
Specifications (M16)
Mass7.5 lb (3.40 kg) (unloaded)[5]
8.81 lb (4.00 kg) (loaded with 30 rounds and sling)[6]
Length39.5 in (1,003 mm)
Barrel length20 in (508 mm)

Cartridge5.56×45 mm NATO (M193)
Caliber5.56 mm (.223 in)
ActionGas-operated, rotating bolt
Rate of fire45–60 rounds/min semi-automatic
700–950 rounds/min cyclic sustained (M16A1)[7]
700-900 rounds/min cyclic sustained (M16A2, M16A3)[8]
800 rounds/min cyclic sustained (M16A4)[8]
Muzzle velocity3,150 ft/s (960 m/s) (M855A1 round)[9]
Effective firing range550 m (601 yd) (point target)[10]
800 m (875 yd) (area target)[11]
Maximum firing range3,600 m (3,937 yd)
Feed systemSTANAG magazine
20-round detachable box magazine:
0.211 lb (96 g) empty / 0.738 lb (335 g) full
30-round detachable box magazine:
0.257 lb (117 g) empty / 1.06 lb (480 g) full)
Beta C-Mag 100-round drum magazine:
2.20 lb (1,000 g) empty / 4.81 lb (2,180 g) full)
SightsIron sights or various optics

In 1964, the M16 entered US military service and the following year was deployed for jungle warfare operations during the Vietnam War.[12] In 1969, the M16A1 replaced the M14 rifle to become the US military's standard service rifle.[13][14] The M16A1's improvements include a bolt-assist, chrome-plated bore and a 30-round magazine.[12]

In 1983, the US Marine Corps adopted the M16A2 rifle and the US Army adopted it in 1986. The M16A2 fires the improved 5.56×45 mm NATO (M855/SS109) cartridge and has a newer adjustable rear sight, case deflector, heavy barrel, improved handguard, pistol grip and buttstock, as well as a semi-auto and three-round burst fire selector.[15][16] Adopted in July 1997, the M16A4 is the fourth generation of the M16 series. It is equipped with a removable carrying handle and Picatinny rail for mounting optics and other ancillary devices.[17]

The M16 has also been widely adopted by other armed forces around the world. Total worldwide production of M16s is approximately 8 million, making it the most-produced firearm of its 5.56 mm caliber.[18][1] The US military has largely replaced the M16 in frontline combat units with a shorter and lighter version, the M4 carbine.[19][20]