The Browning Automatic Rifle (BAR) is a family of American automatic rifles and machine guns used by the United States and numerous other countries during the 20th century. The primary variant of the BAR series was the M1918, chambered for the .30-06 Springfield rifle cartridge and designed by John Browning in 1917 for the American Expeditionary Forces in Europe as a replacement for the French-made Chauchat and M1909 Benét–Mercié machine guns that US forces had previously been issued.
The BAR was designed to be carried by infantrymen during an assault advance while supported by the sling over the shoulder, or to be fired from the hip. This is a concept called "walking fire"—thought to be necessary for the individual soldier during trench warfare. The BAR never entirely lived up to the original hopes of the war department as either a rifle or a machine gun.