The M4A1 carbine is a rifle developed by Colt of the United States and is the first revision of the M4 rifle. The gun is primarily designed with a new flat-top case cover to install a modular aiming system. In August 1994, this flat-top M4 was officially named "5.56mm caliber M4A1 carbine." The main improvement of the M4A1 is to change the original fixed handle to an M1913 guide rail, which can be installed with different aiming devices, that is, a flat top box. In addition, the M4A1's shooting method is semi-automatic and fully automatic. The M4A1 has a range and lethality that is to be proud of, and has a high rate of fire.
Colt's engineers also shortened the barrel to 14.5 inches (370mm). A neck was added to the barrel to mount the M203 grenade launcher. The telescopic stock was used. The shooting method was semi-automatic and fully automatic. A double-layer aluminum heat shield is used. The new Carbine Colt product number is Model 720, which was officially finalized by the military in March 1991 and named "US 5.56mm North Atlantic Treaty Organization caliber M4 Carbine.
The first M4 carbine to participate in the actual battle was in the 1991 Gulf War. Before the outbreak of the war, the US military suddenly found that they lacked new rifles. Many troops were still using M16A1, and M16A2 only began to be equipped in succession in 1986. Many troops have not yet completed their reloading. . Due to the need to obtain a large number of M16A2 and M4 as soon as possible, the U.S. Department of Defense approved the addition of M4 suppliers, and Maine's Bushmaster Firearms received a purchase contract for the supply of M4 carbines and supplied 4,000 to the Army M4. These guns were used by the 82nd Airborne Division during the Desert Shield and Desert Storm. It is said that the guards of General Schwarzkopf also used M4.
Because the M4 and M16A2 are very similar, in fact, 80% of their parts are interchangeable, so they were originally called M16A2 carbines. The M4 was first equipped with the 82 Airborne Division to replace the M16A1 / A2 rifle, M3 submachine gun and some 9mm pistols used by vehicle drivers. It was officially installed in 1994. Colt has also developed a Model 727 with semi-automatic and full-automatic firing methods for the Navy. Except for the firing method, it is exactly the same as the M4, so some people call the Model 727 an M4 enhanced or navy M4.
The M4 carbine has two types of sights that can be used together. One is an optical sight, which is mainly used to replace the current mechanical sight used on the M16A2 rifle. This sight is mainly used during the day. Point, and the red dot is where the bullet will hit. The other is a lightweight thermal imaging sight, which uses the thermal image of the target to determine the target. In addition, considering that the soldier will not have time to adjust the gauge when the enemy encounters the enemy suddenly, the M4 is also equipped with a specially designed firing meter, so that the soldier can directly shoot the gun or its additional device without firing. Perform calibration work.