Imaginations Free

Service history
Type	Carbine
Place of origin	United States
In service	1997–present
Used by	See Users
Wars	War in Afghanistan (2001–present),War in Iraq (2003-2010), Colombian Armed Conflict
Production history
Manufacturer	Colt Defense
Produced	1994–present
Variants	M4A1, CQBR
Specifications
Weight	5.9 lb (2.7 kg) empty 6.9 lb (3.1 kg) with 30 rounds
Length	33 in (838 mm) (stock extended) 29.75 in (756 mm) (stock retracted)
Barrel length	14.5 in (368 mm)

Cartridge	5.56x45mm NATO
Action	Gas-operated, rotating bolt
Rate of fire	700-950 round/min cyclic
Muzzle velocity	2,900 ft/s or 884 m/s
Effective range	500 m for a point target and 600 m for an area target
Feed system	30 round box magazine or otherSTANAG Magazines.

The M4 carbine is a family of firearms tracing its lineage back to earlier carbineversions of the M16, all based on the original AR-15 designed by Eugene Stoner and made by ArmaLite. It is a shorter and lighter version of the M16A2 assault rifle, with 80% parts commonality.

It is a gas-operated, air-cooled, magazine-fed, selective fire, shoulder-fired weapon with a telescoping stock. A shortened variant of the M16A2 rifle, the M4 has 14.5 in(368 mm) barrel, allowing the individual soldier to better operate in close quarters. The M4 has selective fire options including semi-automatic and three-round burst(like the M16A2), while the M4A1 has a "full auto" option instead of three-round burst. The carbine is also capable of mounting an M203 grenade launcher, the M203A1 with a 9-inch barrel as opposed to the standard 12-inch barrel of the M203 used on the M16 series of rifle.

The M4 carbine will eventually replace the M16 rifle for most combat units in the United States Army. The winner of the Individual Carbine competition may replace the M4 carbine in U.S. Army service.

History

The M4 was intended to replace the .45 ACP M3 submachine guns and selected M9 pistols and M16 rifle series with most Army units (this plan was thought to be changed with the development of the XM29 OICW and the XM8 carbine; however, both projects were canceled.)

The United States Marine Corps has ordered its officers (up to the rank of lieutenant colonel) and Staff Non-commissioned officers to carry the M4 carbine instead of the M9 handgun. This is in keeping with the Marine Corps motto, "Every Marine is a rifleman." United States Navy corpsmen will also be issued M4s instead of the M9.

Improved M4

On July 1, 2009, the U.S. Army took complete ownership of the M4 design. This will allow companies besides Colt to compete with their own M4 designs. The Army is planning on fielding the last of its M4 requirement in 2010. On October 30, 2009, Army weapons officials proposed a series of changes to the M4 to Congress. Requested changes include an electronic round counter that records the number of shots fired, a heavier barrel, and replacing the direct impingement system with a gas piston system. As of September 2010 the Army has announced they will buy 12,000 M4A1s from Colt Firearms by the end of 2010 and will by early 2011 order 25,000 more M4A1s. The Army announced also to have open competition for newly designed M4 bolt carrier and gas piston operation system, which will be fitted to the newly bought M4A1 carbines. the army plans to buy 12,000 of these conversion kits in early 2011. In late 2011 the Army plans to buy 65,000 more conversion kits. From there the Army will decide if it will upgrade all of its M4s.

Future Replacement

On November 13, 2008, the U.S. Army hosted an invitation-only Industry Day regarding a potential future replacement for the M4 carbine. Nineteen companies provided displays and briefings for military officials. The weapons displayed included the Barrett REC7 PDW,Bushmaster ACR, FN SCAR, Heckler & Koch HK416, Heckler & Koch XM8, LWRC M6A4, Robinson Arms XCR, SIG 556, as well as Colt's own improved version of the M4, the Colt ACC-M (Advanced Colt Carbine-Monolithic). The goal of the Industry Day was to provide officials with knowledge as to the current state of the art, which will assist the writing of a formal requirements document.

The possible successor to the M4 carbine in the U.S. Army is the Individual Carbine. This program is to provide a new carbine for the Army, while the USMC has decided to stay with the M4 for carbine use.

Design

The M4 and its variants fire 5.56x45mm NATO ammunition (or .223 Remington ammunition) and are gas-operated, air-cooled, magazine-fed, selective fire firearms with a multi-position telescoping stock.^[10] Original M4 models had a flat-ended telescoping stock, but newer models are now equipped with a redesigned telescoping stock that is slightly larger with curvature at the end.The M4 is similar to much earlier compact M16 versions, such as the 1960s-era XM177 family. Some of those visual designs are obvious in both weapons, however most of the similarities are not very noticeable.

As with many carbines, the M4 is handy and more convenient to carry than a full-length rifle. The price is slightly inferior ballistic performance compared to the full-size M16, with its nearly 6" (15 cm) longer barrel. This becomes most apparent at ranges of 300 yards and beyond. Statistically, however, most small-arms engagements occur within 100 yards. This means that the M4 is very much an adequate weapon for the majority of troops. The marginal sacrifice in terminal ballistics and range, in exchange for greatly improved handling characteristics, is usually thought to be a worthwhile compromise.

While the M4's maneuverability makes it a candidate for non-infantry troops (vehicle crews, clerks and staff officers), it also makes it ideal for close quarters battle (CQB). The M4 was developed and produced for the United States government by Colt Firearms, which had an exclusive contract to produce the M4 family of weapons through 2009; however, a number of other manufacturers offer M4-like firearms. The M4, along with the M16A4, have mostly replaced the M16A2 in the Army and Marines. The U.S. Air Force, for example, plans to transition completely to the M4 for security squadrons, while other armed personnel retain the M16A2. The US Navy uses M4A1s for Special Operations and by vehicle crews.

Some features of the M4 and M4A1 compared to a full-length M16-series rifle include:

Compact size
Shortened barrel 14.5 in (368 mm)
Telescoping buttstock

However, there have been some criticisms of the carbine, such as lower muzzle velocities and louder report due to the shorter barrel, additional stress on parts because of the shorter gas system, and a tendency to overheat faster than the M16A2.

M4A1

The M4A1 carbine is a fully-automatic variant of the basic M4 carbine intended for special operations use. The M4A1 has a "S-1-F" (safe/semi-automatic/fully automatic) trigger group, while the M4 has a "S-1-3" (safe/semi-automatic/3-round burst) trigger group. The M4A1 is used by almost all U.S special operation units. The M4A1 is especially favored by counter-terroristand special forces units for close quarters combat because of the carbine's compactness and firepower. These features are also very useful in urban warfare. Although the M4 has less effective range than the longer M16, many military analysts consider engagement with a non-specialized small arm above a range of 300 meters (330 yd) to be unnecessary. It is effective at ranges of 150 meters (160 yd) or less and has a maximum effective range of about 500 to 600 meters (550–660 yd).

In the last few years, M4A1 carbines have been refit or received straight from factory with barrels with a thicker profile under the handguard. This is for a variety of reasons such as heat dissipation, which is useful due to the complaints of high-heat production from test soldiers, which occurs during full-auto and accuracy as a byproduct of barrel weight. These heavier barrel weapons are also fitted with a heavier buffer known as the H2. Out of three sliding weights inside the buffer, the H2 possesses two tungsten weights and one steel weight, versus the standard H buffer, which uses one tungsten weight and two steel weights. These weapons, known by Colt as the Model 921HB (for Heavy Barrel), have also been designated M4A1, and as far as the government is concerned the M4A1 represents both the 921 and 921HB.

Users

Afghanistan: Only used by Afghan Army commandos. M4s sold as part of a 2006Foreign Military Sales package. Additional M4s sold as a 2008 Foreign Military Sales package.
Australia: Used by Special Operations Command, Clearance Divers. and Police Tactical Groups
Bangladesh: Used by Bangladesh Paracommandos, Dhaka Metropolitan Police SWAT teams and Special Warfare Diving And Salvage
Bahrain: M4A1s sold as a 2008 Foreign Military Sales package.
Belize: M4s/M4A1s sold as part of a 2006 Foreign Military Sales package.
Canada: C8 rifle.
Colombia: M4A1s as part of a 2008 Foreign Military Sales.
Ecuador: M4s sold as a 2008 Foreign Military Sales package.
El Salvador: M4s sold as part of a 2007 Foreign Military Sales package. Additional M4s sold as a 2008 Foreign Military Sales package.
Georgia
Greece: Used by EKAM operators
India: M4A1s as part of a 2008 Foreign Military Sales.
Indonesia: Used by Detachment 88 Counter-terrorism Police Squad operators.Also used by Komando Pasukan Katak (Kopaska) tactical diver group and Komando Pasukan Khusus (Kopassus) special forces group.
Iraq: Used by the Iraqi Army. Main weapon of the Iraqi National Counter-Terrorism Force.
Italy: Only Special Forces
Israel: Sold as part of a January 2001 Foreign Military Sales package to Israel.
Jamaica: M4s sold as part of a 2007 Foreign Military Sales package.
Japan: M4A1s as part of a 2008 Foreign Military Sales package.M4A1 SOPMOD rifles are in use by the Japanese Special Forces Group.
Jordan: M4s sold as part of a 2007 Foreign Military Sales package. Additionals M4s sold as a 2008 Foreign Military Sales package.
Lebanon: M4 components being sold to Lebanese special forces. M4/M4A1s sold as a 2008 Foreign Military Sales package.
Macedonia: M4s sold as a 2008 Foreign Military Sales package.

Malaysia: Made under license by SME Ordnance Sdn Bhd. To be used by the Malaysian Armed Forces, special forces ofMalaysian Maritime Enforcement Agency and Royal Malaysian Police.
Nepal: Sold as part of a 2005 Foreign Military Sales package.
New Zealand: Used by NZSAS operators.
Panama: M4A1s sold as a 2008 Foreign Military Sales package.
Philippines: M4/M4A1s sold as a 2008 Foreign Military Sales package.
Poland: Used by Polish special forces unit Grupa Reagowania Operacyjno-Manewrowego (GROM).
Portugal: Used by Marines special forces DAE (Destacamento de Acções Especiais).
Serbia: Used by various police units.
Singapore: Used by the Singapore Armed Forces Commando Formation.
Thailand: M4A1s sold as part of a 2006 Foreign Military Sales package.
Tonga: M4/M4A1s sold as a 2008 Foreign Military Sales package.
Turkey: 12,000 M4/M4A1 carbines in service. Used by Police Special Operation Teams and Army.
United Arab Emirates: Purchased 2,500 M4 carbines in 1993.
United States
Yemen: M4s sold as part of a 2006 Foreign Military Sales package.