Colt M4 – Versatile Carbine

The M4 Carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16, all based on the original AR-15 made by ArmaLite. It is a shorter and lighter version of the M16A2 assault rifle, achieving 80% parts commonality with the M16A2. The M4 has selective fire options including semi-automatic and three-round burst (like the M16A2), while the M4A1 has a “full auto” option in place of the three-round burst.

Colt M4 Carbine is a versatile weapon system with proven combat utility and performance providing the operator with the confidence required to accomplish any mission. Featuring a 14.5 in. (37 cm) barrel it is designed for use wherever lightness, speed of action, mobility and fire power are required. It can be comfortably carried, yet be instantly available to provide the power, accuracy and range of a 5.56mm Rifle. Proven in military operations, it stands alone as a first-line weapon system. Colt M4 Carbine is today’s weapon of choice; the weapon of the 21st century soldier.

The Colt M4 carbine entered service with US Army in 1994. Basically it is a shortenedM16A2 assault rifle with a telescopic buttstock. This carbine was intended as a substitute for submachine guns. It is used by airborne troops, special forces, tank crews, vehicle drivers etc.

Description and Specifications

The M4/M4A1 5.56 mm Carbine is a gas-operated, air-cooled, magazine-fed, selective fire, shoulder-fired weapon with a telescoping stock. A shortened variant of the M16A2 rifle with a 36 cm barrel, the M4 provides the individual soldier operating in close quarters the capability to engage targets at extended range with accurate, lethal fire. The original M4 Carbine has semi-automatic and three-round burst fire modes, while the M4A1 has “semi” and “full auto”, with no three-round burst.

The M4 Carbine is an extremely accurate and effective weapon under all practical field applications. It is a favorite with both first line infantry operations as well as special forces, unit commanders and vehicle crews. Available with a Safe/Semi/Full Auto 3-position selector the M4 Carbine is today?s weapon of choice.

The M4 Carbine features a redesigned 4-position sliding buttstock allowing it to adapt to soldiers of different sizes and physical characteristics as well as various firing positions or clothing variations. Almost all mechanical components are interchangeable with those of the M16 rifle, ensuring quality, commonality of parts and reduced maintenance costs.

The Carbine barrel is designed to accept the M203 Grenade Launcher which can easily be assembled to the carbine offering the user both point and area firing capabilities. Also, all US and NATO rifle grenades can be fired without any supplementary equipment.

The Close Quarters Battle Receiver (CQBR) is a replacement upper receiver for the M4A1 Carbine. The CQBR upgrades the M4 with a barrel 10.3 in (260 mm) long, the modern equivalent of the Colt Commando short-barrel M16 variants of the past.

A CQBR in comparison to a standard M4A1

The M4 and M16 are not ideally suited for all missions, so it was proposed that the modularity of the M16 series would allow a user to replace the upper receiver of an existing weapon with one more suitable to the task. One of two proposed special mission receivers that were planned for inclusion into the SOPMOD Block II kit, the CQBR has taken off on its own. Like the proposed Special Purpose Receiver, the Close Quarters Battle Receiver has been more or less taken on by the Naval Surface Warfare Center, Crane Division (often referred to as NSWC-Crane or just “Crane”) as its own project following the CQBR’s removal from the SOPMOD program. Just as the Special Purpose Receiver morphed into the Special Purpose Rifle, and was type-classified as Mk 12 Mod 0/1, the complete CQBR-equipped carbine has been type-classified as the Mk 18 Mod. 0.

The purpose of the CQBR remains to provide operators with a weapon of submachine gunsize, but firing a rifle cartridge, for scenarios such as VIP protection, urban warfare, and other close quarters battle (CQB) situations. The CQBR is designed to provide improvement over previous AR-15/M16-type weapons in this category. The CQBR is usually issued as a complete weapon system, and not just an upper receiver. The CQBR was once only available to Naval Special Warfare units, but the Mk 18 Mod 0 has become general issue for Visit, Board, Search, and Seizure (VBSS) missions.

The short 10.3 in (262 mm) barrel length requires special modifications to reliably function. The gas port is opened from 0.062 to 0.070 in (0.16 to 0.18 mm). A one-piece McFarland gas ring replaces the three-piece gas ring set. The standard 4-coil extractor spring is replaced with a commercial off-the-shelf (COTS) 5-coil spring. An O-ring surrounds the extractor spring.

Caliber: .223 Rem / 5.56 mm
Cartridge: 5.56 x 45 mm NATO
Weight: 5.9 lb / 2.68 kg empty
Effective range: 660 yd / 600 m
In service: 1994 – present