The Browning Automatic Rifle (BAR) was designed in 1917 by the weapons designer John Browning as a replacement for the French-made Chauchat Light Machine Gun, which was plagued by design flaws that made the weapon ineffective.

The BAR weighs about 20 pounds (9 kg) unloaded, and is fed with a 20 round detachable box magazine loaded from the bottom just behind the foregrip. The BAR could take standard .30-`06 Springfield ammunition, as well as Tracer and Armor-Piercing rounds.

When it was issued as the M1918A1 in the latter days of World War One, Soldiers were issued a "cup" that held the stock of the rifle up to the hip, so the user could lay down suppressing fire whilst moving. The M1918A1 also had semiautomatic fire and an attached spiked bipod.

In 1940, the M1918A2 was issued to troops that were yet to fight in combat. It removed Semi-Automatic fire in favor of a Rate of Fire selector switch, located on the trigger guard that allowed the user to go from 300-450 RPM (slow) and 500-650 RPM (fast). It also improved the stock using a buffer spring in the butt of the rifle. Also, the M1918A2 came with a bipod that weighed 2 pounds. Most soldiers discarded the bipod to reduce the weight they had to carry, though it proved useful while prone in a defensive role.

It served from the latter days of World War One, into World War Two and ultimately ended its service shortly before the Vietnam War.