U.S. combat rifle M14 rifle with a 7.62 × 51 mm NATO bullet and single/continuous firing capability

 The American Rifle ( , M14) was an American combat rifle with a 7.62 × 51 mm NATO rifle and single - shot capability. Mostly replaced by M16 rifles in the United States Army, U.S. Marine Corps, and U.S. Navy, but limited use in the nama fields is limited. The M14 rifle is also the basis for the M21 sniper rifle and the M25 sniper rifle. It was also the type of rifle used only for five years (1959–1964), the shortest time in American history.

The M14 EBR (Mk.14 EBR) is now modernized and used as a support rifle, and is used by the U.S. Marine Corps as an M39 EMR designated rifle to increase the length of the gun and remove the automatic firing system. In the United States, the M1A is sold to the private sector as a semi-automatic rifle, and is mainly used in hunting guns and shooting sports over the size of deer.

In 1943, the ministry planned to completely and automatically renovate the M1 Galland. After research, the T20 was created in 1945 under the leadership of M1 designer John C. Garland. The overall shape is almost the same as the existing M1, with a semi-automatic/automatic selector lever attached directly to the side of the pharmacy, the existing spring can be pulled to fit the cartridge of the BAR (pharmacy design, brass, cartridge stoppers are almost the same as the mass production of the M14 currently in use).

However, after the end of World War II in 1948, the improvement project was suspended in the aftermath of the contraction of the military industry, but the project was resumed due to the outbreak of the Korean War. During the Korean War, the M1 and M1 carbines used by the U.S. military in World War II were still officially used. The project for the M14 was experimented with guns of significantly different designs, such as the T25 and T37, but eventually the T44E4, which was actually redesigned for the existing T20, was chosen after competing with the T48 (FAL) and was formally adopted under the M14.

​The M14 was hired shortly before the outbreak of the Vietnam War and is recorded as the first combat rifle used by the U.S. military in the Vietnam War. However, the M14 was a form of development of the M1 Grand, based on the flat and temperate climates of the United States and Europe, which showed a major drawback in the wooded and humid jungle wars.

The biggest problem was that it was difficult to control the gun due to the M14's counter-attack when automatic shooting to attack hidden enemies in the jungle. Moreover, the long barrel made it difficult to move in the jungle, and the weather in Vietnam easily corroded wooden dogheads, and was too heavy a rifle for soldiers who had to walk on muddy roads. 

​Moreover, the rifle was too long to carry for the U.S. military, which was about 173cm tall on average, so it was too large for the Vietnamese army, which was about 160cm tall on average. As a result, the M16 rifle using a 5.56 x 45 mm NATO bullet developed by Eugene Stoner was removed from the formula.

​Currently, it is not fully retired, and is used by the U.S. military as a designated military rifle to support engagement, focusing on platoon or company units.

In the Vietnam War, the modified M14 was used by snipers, was called the XM21 and was officially hired as the M21 in 1975. On the other hand, another variant is the M25 and M1A, which are still produced for civilian use, and there was no selector lever that allowed only semi-automatic. 

​On the other hand, according to the reuse trend of M14, many modified guns have recently been released to change wooden guns into plastic resins and reduce weight or length, and a small number of Mk 14 Mod 0 EBR (M14 EBR) are currently employed and used by the U.S. military. In addition, the M14A1, M14E1, and M15 are used as squad support firearms with a pistol handle attached to the M14. 

In addition, Mk14 Mod0 EBR (M14 EBR), a modernized version of M14, is currently used in a minority. The U.S. Marine Corps makes and uses the M39 EMR, which increases the length of the gun heat and removes the automatic launcher for designated purposes.