| Carbine, 5.56 mm, M4 | |
|---|---|
 An M4 with Rail Adapter System (RAS), flip-up rear sight, vertical forward grip with bipod and the latest Aimpoint M68 CCO. | |
| Type | Carbine |
| Place of origin |  United States |
| Service history | |
| 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) 29.8 in (757 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[1] |
| Muzzle velocity | 2,900 ft/s or 884 m/s[1] |
| Effective range | 393 yd (360 m) [1] |
| Feed system | 30 round box magazine or other STANAG Magazines. |
M4 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 designed by Eugene Stoner and made by ArmaLite. It is a shorter and lighter version of the M16A2 assault rifle, with 80% parts commonality.[2]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 possible successor to the M4 carbine in the U.S. Army is the Individual Carbine.[3]
Overview
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.[4] 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. [5] 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.
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;[citation needed] however, a number of other manufacturers offer M4-like firearms. The M4A1, 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. They maintain a yearly qualification with the carbine.
The United States Marine Corps has ordered its officers (up to the rank of lieutenant colonel) and Staff Non-commissioned officers to carry the M4A1 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 M4A1s instead of the M9.[6]
[edit] History and variants
For more details on M4 carbine variants, see AR-15 variants
Except for the very first delivery order, all U.S. military-issue M4 and M4A1 possess a flat-top NATO M1913-specification (Picatinny) rail on top of the receiver for attachment of optical sights and other aiming devices — Trijicon TA01 and TA31 Advanced Combat Optical Gunsights (ACOG), EOTech 550 series holographic sights, and Aimpoint M68 Close Combat Optic (M68 CCO) being the favorite choices — and a detachable rail-mounted carrying handle. Standards are the Colt Model 920 (M4) and 921 (M4A1).Variants of the carbine built by different manufacturers are also in service with many other foreign special forces units, such as the Australian Special Air Service Regiment (SASR). While the SASR uses weapons of essentially the same pattern built by Colt for export (Colt uses different models to separate weapons for the U.S. military and those for commercial/export purposes), the British SAS uses a variant on the basic theme, the Colt Canada (formerly Diemaco) C8SFW.
[edit] M4 MWS (Modular Weapon System)
[edit] 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-terrorist and 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).[7]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.
[edit] SOPMOD Block I
[edit] SOPMOD Block II
A second-generation SOPMOD kit (now known as SOPMOD II) is currently under development, with many different manufacturers competing for the contract. Notable bidders include Knight's Armament Company, Atlantic Research Marketing Systems (ARMS), and Lewis Machine & Tools. Daniel Defense has won the contract for the RIS-II, the next generation of rail handguards.[edit] Improved M4
On July 1, 2009, the U.S. Army took complete ownership of the M4 design.[8] 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.[8] 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.[9] As of September of 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.[10][edit] Future replacement
See also: M16 Future Replacement
The carbine variant of the XM8 rifle was canceled in 2005.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.[11]
The possible successor to the M4 carbine in the U.S. Army is the Individual Carbine.[3] This program is to provide a new carbine for the Army, while the USMC has decided to stay with the M4 for carbine use.[10]
[edit] Design
Some features of the M4 and M4A1 compared to a full-length M16-series rifle include:
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.
[edit] Accessories
Like all the variants of the M16, the M4 and the M4A1 can be fitted with many accessories, such as night vision devices, suppressors, laser pointers, telescopic sights, bipods, either the M203 or M320 grenade launchers, the M26 MASS shotgun, and anything else compatible with a MIL-STD-1913 Picatinny rail.
Other common accessories include the AN/PEQ-2, Advanced Combat Optical Gunsight (ACOG), and M68 CCO. EOTech holographic weapon sights are part of the SOPMOD II package. Visible and IR (infrared) lights of various manufacturers are also commonly attached using various mounting methods. As with all versions of the M16, the M4 accepts a blank-firing attachment (BFA) for training purposes.
[edit] Effectiveness
An April 2002 presentation by the US Army Natick Soldier Center presented by LTC Charlie Dean and SFC Sam Newland reported on lessons learned from M4 use in Afghanistan (such as use during Operation Anaconda):[citation needed]- 90% of soldiers reported confidence in the weapon.
- 20% were dissatisfied with its need of maintenance.
- 34% of soldiers reported that their M4's handguards rattled and became excessively hot when firing.
- 15% reported that they had trouble zeroing the M68 reflex sight.
- 35% added barber brushes and 24% added dental picks to their cleaning kits.
- Soldiers reported the following malfunctions:
- 20% reported double-feeding.
- 15% reported feeding jams.
- 13% reported that feeding problems were usually due to magazines.
- 55% requested the firearm be made lighter.
- 20% requested a slightly larger magazine.
[edit] 2007 dust test
In the fall 2007, the Army tested the M4 against three other carbines in "sandstorm conditions" at Aberdeen Proving Ground, Maryland: the Heckler & Koch XM8 rifle, Fabrique Nationale de Herstal SOF Combat Assault Rifle (SCAR) and the Heckler & Koch HK416. Ten of each type of rifle were used to fire 6,000 rounds each, for a total of 60,000 rounds per rifle type.[12] The M4 suffered far more stoppages than its competitors: 882 stoppages, 19 requiring an armorer to fix. The XM8 had the fewest stoppages, 116 minor stoppages and 11 major ones, followed by the FN SCAR with 226 stoppages and the HK416 with 233.[13][14] The Army was quick to point out that even with 863 minor stoppages—termed "class one" stoppages which require 10 seconds or less to clear and "class two" stoppages which require more than ten seconds to clear—the M4 functioned well, with over 98 percent of the 60,000 total rounds firing without a problem. The Army said it planned to improve the M4 with a new cold-hammer-forged barrel to give longer life and more reliable magazines to reduce the stoppages. Magazine failures caused 239 of the M4's 882 failures. Army officials said the new magazines could be combat-ready by spring if testing went well.[15][edit] Gas Piston
Complicating the Army search for higher effectiveness in the M4 is a number of observations of M4 gas piston alternatives that suffer unintended design problems. The first is that many of the gas piston modifications for the M4 isolate the piston so that piston jams require the entire weapon be disassembled. The second is that gas piston alternatives use an off-axis operation of the piston that can introduce carrier tilt, whereby the bolt carrier fails to enter the buffer tube at a straight angle resulting in part wearing. The third is that the use of a sound suppressor results in hot gases entering the chamber, regardless of a direct-gas impingement or gas piston design choice.[16][edit] Trademark issues
No comments:
Post a Comment