Colt M16 (M16A1)
Colt's Manufacturing Company · Assault Rifle · Limited Production · 1964
Also known as: Rifle, 5.56mm, M16, Rifle, 5.56mm, M16A1, Colt Model 601, Colt Model 602, Colt Model 603, AR-15 (Military), XM16E1
Overview
The Colt M16 is a lightweight, air-cooled, gas-operated, magazine-fed assault rifle chambered in 5.56x45mm that became the standard United States military service rifle in the mid-1960s, replacing the heavier M14. Originally designed by Eugene Stoner at ArmaLite as the AR-15, the design was sold to Colt in 1959 and adopted by the U.S. Air Force as the M16 in 1964. The improved M16A1 variant, featuring a forward assist, chrome-lined chamber, birdcage flash hider, and closed bolt operation, was type-classified in 1967 and became the standard infantry weapon during the Vietnam War. The rifle uses a direct impingement gas system with a rotating bolt, feeding from 20-round (later 30-round) STANAG magazines. Its 1:12 rifling twist was optimized for the 55-grain M193 ball cartridge. Despite early reliability controversies in Vietnam stemming from propellant changes and inadequate cleaning, the M16A1 proved itself as an effective combat weapon and spawned a family of variants that has served continuously for over sixty years. More than 8 million M16-pattern rifles have been produced worldwide.
Specifications
| Weight (empty) | 2890 g (101.9 oz) |
| Weight (loaded) | 3610 g (127.3 oz) |
| Overall Length | 986 mm (38.82") |
| Barrel Length | 508 mm (20.00") |
| Height | 248 mm (9.76") |
| Width | 64 mm (2.52") |
| Sight Radius | 500 mm (19.69") |
| Action Type | Gas Operated Direct Impingement |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Magazine Capacity | 20 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 991 m/s (3251 fps) |
| Muzzle Energy | 1796 J (1325 ft·lbf) |
| Effective Range | 460 m (503 yd) |
| Maximum Range | 2653 m (2901 yd) |
| Rate of Fire | 800 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 305 mm (12.01") |
| Number of Grooves | 6 |
| Frame Material | Aluminum Alloy |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Hard Anodized |
Calibers
- 5.56x45mm NATO · primary · SS109 / M855 — also known as 5.56 NATO, 5.56x45, .223 Remington
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety Selector, Half Cock Notch
- Features: Fixed Stock, Select Fire, Full Automatic, Direct Impingement Gas System, Rotating Bolt, Chrome Lined Chamber, Forward Assist, Brass Deflector, Birdcage Flash Hider, Triangular Handguards, Fixed Carrying Handle, Pistol Grip, Inline Stock Design
Variants
- M16 (Original, Colt Model 601/602) — Original
- XM16E1 — Prototype
- Colt M16A2 — Improved
- M16A3 — Full Auto A2
- Colt M16A4 — Flat Top Receiver
- M4 Carbine — Carbine
- M4A1 Carbine — Carbine
- Diemaco C7 — Canadian Variant
- AR-15 (Civilian) — Semi Auto Civilian
Service history
Operators
- United States Air Force · adopted 1964 · as M16
- United States Army · adopted 1967 · as M16A1
- United States Marine Corps · adopted 1967 · as M16A1
- Army of the Republic of Vietnam · adopted 1966 · as M16/M16A1
- Israel Defense Forces · adopted 1973 · as M16A1
- Philippine Armed Forces · adopted 1966 · as M16A1
- Royal Thai Armed Forces · adopted 1967 · as M16A1
- Australian Defence Force · adopted 1967 · as M16A1
- New Zealand Defence Force · adopted 1967 · as M16A1
- Republic of Korea Armed Forces · adopted 1968 · as M16A1
- British Special Air Service · adopted 1966 · as M16
- Colombian National Army · adopted 1969 · as M16A1
- Indonesian National Armed Forces · adopted 1975 · as M16A1
- Salvadoran Armed Forces · adopted 1980 · as M16A1
- Jordanian Armed Forces · adopted 1970 · as M16A1
Conflicts
- Vietnam War (1964-1975)
- Cambodian Civil War (1967-1975)
- Laotian Civil War (1964-1975)
- Dominican Civil War (1965)
- Yom Kippur War (1973)
- Iranian Revolution (1978-1979)
- Lebanese Civil War (1975-1990)
- Salvadoran Civil War (1979-1992)
- United States invasion of Grenada (1983)
- United States invasion of Panama (1989-1990)
- Gulf War (1990-1991)
- Somali Civil War (1992-1995)
Production
Estimated total produced: 8,000,000 · Production years: 1959-present
Over 8 million M16-pattern rifles produced by Colt, General Motors Hydramatic Division, Harrington & Richardson, FN Herstal, Elisco (Philippines), and numerous other licensees worldwide. The original M16 and M16A1 were produced primarily 1959-1983.
Origin
Country of origin: United States
Designer: Eugene Stoner
Notes
The original M16 (Colt Model 601/602) lacked a forward assist and had a three-prong flash hider. It used a 1:14 rifling twist, later changed to 1:12 for the production M16. The XM16E1 added the forward assist and was redesignated M16A1 in 1967 with further improvements including a chrome-lined chamber, 30-round magazine compatibility, and the distinctive birdcage flash suppressor. The M16A1 originally fired M193 ball ammunition (55-grain at 3,250 fps), NOT the later NATO SS109/M855 round used by the M16A2 and later variants. Early reliability problems in Vietnam were traced to a change from IMR stick powder to ball powder (WC846) which increased cyclic rate and fouling, combined with the Army's initial failure to issue cleaning kits or train soldiers on weapon maintenance. The direct impingement system channels propellant gas directly into the bolt carrier, which critics termed 'shitting where it eats' due to carbon buildup. The rifle's light weight (under 3 kg empty) was revolutionary for a full-power military rifle.
Background
The M16's troubled introduction in Vietnam is one of the most infamous equipment failures in American military history. Soldiers reported rifles jamming in combat, leading to Congressional investigations. The root cause was a Pentagon decision to switch from IMR4475 stick propellant to WC846 ball powder without adequate testing, which increased the cyclic rate by 100 RPM, produced excessive fouling, and corroded the non-chrome-lined chambers. The Army's initial claim that the rifle was 'self-cleaning' and its failure to issue cleaning kits or provide maintenance training compounded the disaster. After these issues were resolved with chrome-lined chambers, proper cleaning procedures, and the return to proper propellant specifications, the M16A1 proved itself as an excellent combat weapon that American soldiers grew to trust. Eugene Stoner's revolutionary inline stock design, which placed the recoil spring in the buttstock directly behind the bolt carrier, dramatically reduced muzzle climb during automatic fire compared to conventional rifles. The aluminum receiver and polymer furniture made it far lighter than any contemporary battle rifle, a breakthrough that fundamentally changed military small arms design.