An automatic rifle is a man-portable infantry weapon capable of automatic fire, chambered in a full-power rifle cartridge. An automatic rifle chambered in an intermediate rifle cartridge could typically be classified as an assault rifle. Automatic rifles are also distinct from machine guns in that they are designed to be operated by a single man rather than a crew.
The term "automatic rifle" is now considered antiquated and is rarely used in a modern context. Conceptually equivalent weapons are now classified as assault rifles, battle rifles, or light machine guns.
- Browning Automatic Rifle - perhaps the most well-known example of an automatic rifle, adopted by the U.S. Army in 1918 and fielded during both World Wars. Also adopted by various other countries.
- Chauchat - French-made automatic rifle adopted in 1915 and used as an assault weapon during the trench combat of World War I.
- Fedorov Avtomat - Light automatic rifle developed in Russia during World War I, often considered a precursor of the assault rifle concept.
- FG 42 - German 7.92×57mm automatic rifle, extensively employed by parachutists during World War II.