The M4 carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16 rifle, all based on the original AR-15 rifle designed by Eugene Stoner and made by ArmaLite. The M4 is a shorter and lighter variant 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 a 14.5 in (370 mm) barrel, allowing its user to better operate in close quarters combat. The M4 has selective fire options including semi-automatic and three-round burst (like the M16A2 and M16A4), while the M4A1 has the capability to fire fully automatic instead of three-round burst (like the M16A1 and M16A3). 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) as well as its successor, the M320 grenade launcher.
The M4 carbine is heavily used by the U.S military. It is slated to eventually replace the M16 rifle for most combat units in the United States Army. The winner of the Individual Carbine competition might supplement the M4 carbine in U.S. Army service. This is for the US Army only while all other services will continue to use the M4 carbine and M16 rifles.
Following the adoption of the M16, carbine variants were also adopted for close quarters operations. The CAR-15 and its variations served through the Vietnam War. However, these carbines had design issues. They were primarily made for close ranges, like submachine guns, and so suffered at longer ranges. In 1988, Colt began work on an new carbine design called the XM4 based on their M16A2 rifle. To remedy the range problem, Colt incorporated a 14.5 inch barrel, giving the weapon greater reach than the CAR-15 while still being more compact than the M16. The extended barrel gave the XM4 the ability to mount a shortened M203 grenade launcher. In 1994, the U.S. military officially accepted the XM4 into service as the M4 Carbine to replace the M3 Grease Gun, as well as selected M9 pistols and M16A2 rifles.
The carbine variant of the XM8 rifle was cancelled in 2005.
The M4 and its variants fire 5.56×45mm NATO ammunition (and .223 Remington ammunition) and are gas-operated, air-cooled, magazine-fed, selective fire firearms with either a multi-position telescoping stock or a fixed A2 or LE tactical stock. 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.
The M4 with the newer, redesigned telescoping stock
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. A very large proportion of US forces engagements in the recent middle-east conflicts has consisted of MOUT, therefore justifying the choice.
On 13 November 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, Remington 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. 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.
- The M4 Carbine was about 477 Dollars on Military Fire Arms.Net, marking it one of the most Expensive Assault Rifles on the Internet due to it being 21st Century tech...