M4A1 Carbine
Colt's Manufacturing Company · Carbine · In Production · 1994
Also known as: Carbine, 5.56mm, M4A1, Colt Model 921, SOPMOD M4A1
Overview
The M4A1 Carbine is a select-fire carbine chambered in 5.56x45mm NATO, produced by Colt's Manufacturing Company since 1994. Featuring a 30-round magazine capacity, this carbine offers generous firepower for duty use and home defense.
Specifications
| Weight (empty) | 2886 g (101.8 oz) |
| Weight (loaded) | 3456 g (121.9 oz) |
| Overall Length | 756 mm (29.76") |
| Folded Length | 757 mm (29.80") |
| Barrel Length | 368 mm (14.49") |
| Action Type | Gas Operated Direct Impingement |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Trigger Pull | 34 N (7.6 lbf) |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 905 m/s (2969 fps) |
| Muzzle Energy | 1640 J (1210 ft·lbf) |
| Effective Range | 500 m (547 yd) |
| Maximum Range | 3600 m (3937 yd) |
| Rate of Fire | 850 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Aluminum Alloy |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Hard Anodized |
Calibers
- 5.56x45mm NATO · primary · 5.56x45mm NATO — also known as 5.56mm NATO, 5.56x45mm, .223 Remington
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety Selector, Half Cock Notch
- Features: Collapsible Stock, Select Fire, Accessory Rail, Chrome Lined Barrel, Chrome Lined Chamber, Rotating Bolt, Flat Top Receiver, Picatinny Rail
Variants
- M4 — Burst Fire
- Mk 18 Mod 0 — Short Barrel
- Mk 18 Mod 1 — Short Barrel
- CQBR — Close Quarters
- M4A1 SOPMOD — Special Operations
- M4A1 URG-I — Improved Upper
Service history
Operators
- United States Armed Forces · adopted 1994 · as M4A1
- United States Special Operations Command · adopted 1994 · as M4A1
- Australian Special Air Service Regiment · as M4A1
- British Special Air Service · as C8SFW
- Japan Special Forces Group · adopted 2008 · as M4A1 SOPMOD
- Israel Defense Forces · adopted 2001 · as M4A1
- Polish Special Forces · as M4
- German Armed Forces · as M4
- Italian Armed Forces · as M4
Conflicts
- War in Afghanistan (2001-2021)
- Iraq War (2003-2011)
- War on Terror (2001-present)
Production
Estimated total produced: 500,000 · Production years: 1994-present
M4/M4A1 combined; produced by Colt, FN America, and Remington Defense
Origin
Country of origin: United States
Designer: Eugene Stoner
Notes
The M4A1 differs from the standard M4 in having full-automatic capability instead of 3-round burst fire. The barrel was also thickened to better dissipate heat during automatic fire. The weapon features a flattop receiver with Picatinny rail for mounting optics and accessories. Chrome-lined barrel and chamber provide enhanced durability and corrosion resistance. Production is now shared among multiple manufacturers including FN America, Colt, and Remington Defense. The Mk 18 CQBR variant features a shortened 10.3-inch barrel for close-quarters combat. The weapon has undergone over 90 modifications since initial adoption to improve adaptability, ergonomics, and modularity.
Background
The M4A1 became the standard-issue weapon for nearly all U.S. military personnel in 2015, completing a transition from the full-length M16 that began in the 1990s. The SOPMOD (Special Operations Peculiar Modification) accessory kit transformed the M4A1 into the most modular weapon system in military history, with over 90 approved accessories.