M4 Carbine

The M4 Carbine is a select-fire assault rifle developed by the United States and produced in 1994. A derivative of the M16 Rifle series, it presents a more compact firearm for nearly the same firepower. This weapon fires 5.56x45mm. The most notable feature on this carbine, like its M16 family, is the ability to equip various accessories due to Picatinny rails on its hand guards and on the top receiver. Currently, the carbine is fielded in 50+ countries.

History
The M16 rifle was adopted in 1962. Though capable for the job, the 20-inch barrel on the rifle cause an interest in carbine variants for much closer distance combat than the typical rifle will experience. Experimental weapons such as XM177 of the CAR-15 family turned up as a result with a barrel length of only 10 inches. While short, its effective range was cut and the noise and muzzle flash increases. Though these are a solution to the carbine variant of the M16, these were made in the Vietnam-Era. Modern technology would march on to create the M4 carbine.

In the early 1980s, United States began a program to upgrade their M16A1 rifles to the now M16A2. The new features present on the M16A2 is then implemented to the CAR-15 series, and in 1988, the resulting design is called XM4. Unlike the CAR-15 series, the XM4 has a 14.5 inches barrel which gives a lower noise and muzzle flash that the CAR-15 gave, and also allows attachment of the M203 grenade launcher or bayonet. The XM4 also took the M16A2 features of the new rear sight design, cartridge deflector, and other smaller modifications. The XM4 then became accepted by the United States military in 1994 as the M4 Carbine. Its compactness is greatly valued as it could replace most submachine guns in current military service and while allowing superior firepower that has superior stopping power and body armor penetration.

M4
The original M4 with a safe/semi/3-round burst trigger group for select fire.

M4A1
A fully-automatic variant of the M4 Carbine. Intended for special forces, it did away with the 3-round burst trigger group for a safe/semi/automatic trigger group. Arguably, the fully automatic trigger group gave the carbine a more consistent trigger pull as the burst group has caused the trigger to be highly varied in trigger pull, degrading accuracy.

Mk 18 CQBR
A more compact variant of the M4 carbine, reducing the barrel from 370 mm to 262 mm. Designed by the U.S. Navy, it was made for more compact use than the M4 carbine can provide. However, the short barrel causes extra modifications to be made to the design in order to reliably function. It has the trigger group Safe/semi/automatic.

Aleto Use
The M4 Carbine has become a favorite among Aleto forces due to its widespread use and its capability of adaption to different situation. Most Western-influenced foces has the M4 Carbine as part of its arsenal.