During the 1991 Gulf War, the United States left a deep impression on all countries in the world with all kinds of new equipment and new tactics, and the various forms of M4 rifles in the hands of the US military at that time became one of the calling cards of the US military. With the cancellation of the American XM8 rifle program, the M4 rifle (including the M16 rifle) became the longest-serving standard rifle in the United States, and many people said that the M4 rifle was the best rifle.
After World War II, the United States fully replaced the M14 automatic rifle, due to the use of 7.62mm full-power ammunition, its power is high, and the firepower density is also greatly improved compared with the M1 Garand semi-automatic rifle used during World War II. It is precisely because of the use of full-power bullets, which still have lethality at a distance of 2000 meters, which is obviously excessive, and the recoil of full-power bullets is very large, so it is very difficult to master when shooting fully automatically, plus the 7.62x51 mm full-power bullets are relatively large in size and weight, compared with the AK-47 of the same caliber in the Soviet Union at that time, the ammunition carrying capacity is also less in the case of the same weight, so the United States developed a new small-caliber rifle M16.
The M16 uses a 5.56x45mm NOTO bullet, although the caliber of this bullet is much smaller, but because the small-caliber bullet will roll in the body after hitting the human body to produce a cavity, that is to say, although the caliber of this bullet is smaller, but the lethality has not been reduced. Due to the reduced charge, the recoil is also greatly reduced, easier to maneuver, and the accuracy of the continuous firing state is higher. However, the early M16 due to a variety of reasons such as manufacturing technology and maintenance parts are not in place, when it first arrived in the Vietnam battlefield, frequent failures, reliability is very poor, although the U.S. military reissued maintenance parts, the reliability of M16 has been greatly improved, but the U.S. Army is still not satisfied with M16. So the United States improved the M16A1 on the basis of the M16, and then developed the M16A2 on the basis of the M16A1, and then further developed the M16A3 and M16A4.
In 1988, the U.S. Army awarded Colt to develop a new and improved carbine in conjunction with the Department of the Army and the Marine Corps, and in 1991 The United States Carbine, the Caliber 5.56 mm NATO, M4 (American 5.56 mm North Atlantic Treaty Organization caliber M4 carbine) was born. The M4 basically follows the structure of the M16, using the same air-conductive, air-cooled, rotating bolt design, using magazines to feed ammunition, and the magazines are interchangeable.
80% of the parts between the M4 and M16 were interchangeable, so the two guns were so similar that the early M4 was reloaded to the 82nd Airborne Division under the number M16A2 to replace the M16A1, M3 submachine guns and some 9mm pistols used by vehicle drivers. In fact, the M4 is more like the short-barreled version of the M16, and the M4 uses a telescopic butt with adjustable length, so the M4 is more convenient to use in small environments such as urban combat, jungle warfare and shooting in armored vehicles, which is very in line with the needs of the US military at that time.
Colt also mounted a Picatinny rail to the M4 rifle, making it very easy to attach and remove tactical accessories. Thanks to the standard rails of this quick-release design, the M4 gains modularity and can be equipped with a wide range of accessories including low-magnification scopes, tactical flashlights, infrared laser sights, night vision devices, and grenade launchers, depending on the mission. This is how the "fitness equipment" and "Christmas tree" that are very familiar to those who like to play war games come about. And it is precisely because the M4 can be configured with different tactical accessories to enhance its combat capability according to different tasks, so that the M4 has good performance in various tasks of the US military. It can be said that it is a "reliable partner" in the operation of the US military, which is one of the reasons why many people consider the M4 rifle to be the most excellent.
In addition to the convenience of installing a wealth of tactical accessories, the M4 rifle itself has also been continuously improved and developed, and various models such as M4A1 and SOPMOD M4 have been continuously developed. At the same time, the short-barreled CQB M4, which is more suitable for indoor and street fighting, and the Colt 921HB (still officially named M4A1) with a thickened barrel were also developed, as well as the M4, which can fire 7.62mm ammunition, and the SR25 precision marksman rifle and M110 precision marksman rifles, which were developed from the M4 and M16. This further makes the M4 rifle sufficient for all the operational needs of the United States.
In addition, the M4 is a NATO standard rifle implemented by the U.S. military, and the matching 5.56x45mm NOTO bullet is used as NATO standard equipment, which makes a large number of countries equipped with M4 rifles, which also makes M4 have a huge production capacity and a wide range of use bases all over the world. In fact, this also means that even if you go abroad to fight, it is not difficult to get accessories for the M4. This, coupled with the fact that almost all NATO countries are using 5.56x45mm NOTO shells, also means that logistics supply and maintenance, as well as training, can be greatly simplified.
For example, since the 1991 Gulf War, the M4 rifle has participated in all U.S. ground operations in foreign wars, and the success of these ground operations is undoubtedly due to the M4 rifle. In 2011, during bin Laden's beheading, Navy SEALs killed bin Laden by aiming an infrared laser point from an M4 rifle at bin Laden's chest. So for the United States, the M4 rifle can be described as a great achievement.
It is precisely because the M4 rifle has good performance and strong actual combat performance that many people say that the M4 rifle is the best rifle. However, if the M4 rifle is the best rifle, then why did the United States start replacing the M4 rifle and M249 machine gun in the first battalion of the 101st Infantry Regiment of the 506th Airborne Division in April this year with a new M7 rifle and M250 squad machine gun? In fact, the replacement of M7 by the United States solves the biggest pain point of the M4 rifle, the problem of low lethality of 5.56 rounds, and the biggest feature of the M7 rifle and M250 machine gun replaced by the United States is the use of 6.8mm rifle cartridges to solve the problem of insufficient lethality of 5.56.
When the United States switched from 7.62 full-power ammunition to 5.56 small-caliber ammunition in the fifties and sixties of the last century, the problem of 7.62 full-power ammunition at that time was that it was too lethal, and most of the damage caused to the target was penetrating wounds. As mentioned above, although the power of the 5.56 bullet is much smaller, the destructive power to the target is not less than that of the 7.62 bullet due to the cavity generated by rolling in the target's body after hitting the target. At the same time, the 5.56 bullet will consume a lot of kinetic energy when rolling, and the bullet will basically stay in the target's body, and the remaining kinetic energy will be very small even if it penetrates, which is very suitable for street combat and indoor close-range combat use, which are the advantages of the combat environment faced by the United States at that time.
With the development of the times, first of all, the combat environment has changed, the United States often needs long-distance shooting when fighting on the plains like Afghanistan, and the effective range of the M4 is only 500 meters, which can not meet the needs of the troops in many cases, so many soldiers feel that the power and range of the M4 rifle are small. In addition, with the popularization of body armor, the shortcomings of the 5.56 bullet itself with poor penetration are more exposed, and in the face of body armor, the power or kinetic energy of the 5.56 bullet cannot penetrate the body armor. In addition, the M4 on the battlefield in Afghanistan also exposed problems such as high firing noise and overheating of the barrel.
It is fair to say that the M4 rifle is a very good rifle that has performed well over the past few decades, but just as there is no perfect person, there is no perfect weapon. Even though the M4 has such and such advantages, the disadvantages are also very obvious, and some of them are still hard, so it cannot be said that the M4 is the best rifle, because the better rifle is always the next generation.