M16 rifle

Rifle, Caliber 5.56 mm, M16
M16A2, multi-sided view
TypeAssault rifle
Place of originUnited States
Service history
In service1964–present
Used bySee Users
WarsSee Conflicts
Production history
DesignerEugene Stoner (AR-10)
L. James Sullivan (AR-15)
Designed1959
Manufacturer
Produced
  • November 1963–present
No. built~8 million
VariantsSee List of Colt AR-15 and M16 rifle variants
Specifications (M16)
MassUnloaded:
6.37 lb (2.89 kg) (M16A1)
7.5 lb (3.40 kg) (M16A2 without magazine and sling)
7.5 lb (3.40 kg) (M16A4)
8.81 lb (4.00 kg) (M16A4 loaded with 30 rounds and sling)
Length38.81 in (986 mm) (M16A1)
39.63 in (1,007 mm) (M16A2)
39.37 in (1,000 mm) (M16A4)
Barrel length20 in (508 mm)

Cartridge5.56×45mm NATO
ActionGas-operated, closed rotating bolt, Stoner bolt and carrier piston
Rate of fire700–800 rounds/min cyclic sustained (M16A1)
700–900 rounds/min cyclic sustained (M16A2, M16A3)
800 rounds/min cyclic sustained (M16A4)
Muzzle velocity3,150 ft/s (960 m/s) (M855A1 round)
Effective firing range550 m (601 yd) (point target)
800 m (875 yd) (area target)
Maximum firing range3,600 m (3,937 yd)
Feed systemSTANAG magazine
20-round detachable box magazine
30-round detachable box magazine
40-round detachable box magazine
60-round detachable box magazine
Beta C-Mag 100-round drum magazine
SightsIron sights:
Rear: aperture; L-type flip
Front: wing-protected post
Various aiming optics

The M16 (officially Rifle, Caliber 5.56 mm, M16) is a family of assault rifles adapted from the ArmaLite AR-15 rifle for the United States military. The original M16 was a 5.56×45mm automatic rifle with a 20-round magazine.

In 1964, the XM16E1 entered US military service as the M16 and in the following year was deployed for jungle warfare operations during the Vietnam War. In 1969, the M16A1 replaced the M14 rifle to become the US military's standard service rifle. The M16A1 incorporated numerous modifications including a bolt-assist ("forward-assist"), chrome-plated bore, protective reinforcement around the magazine release, and revised flash hider.

In 1983, the US Marine Corps adopted the M16A2 rifle, and the US Army adopted it in 1986. The M16A2 fires the improved 5.56×45mm (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. Adopted in July 1997, the M16A4 is the fourth generation of the M16 series. It is equipped with a removable carrying handle and quad Picatinny rail for mounting optics and other ancillary devices.

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. The US military has largely replaced the M16 in frontline combat units with a shorter and lighter version, the M4 carbine. In April 2022, the U.S. Army selected the SIG MCX SPEAR as the winner of the Next Generation Squad Weapon Program to replace the M16/M4. The new rifle is designated M7.