US light machine gun used for infantry support, adopted by the US Army 1917 and standard issue until the early 1950s. It used a 20-shot magazine and fired 500 rounds per minute.
It was originally intended for use in a newly developed French tactic, “marching fire” in which advancing troops fired from the waist during their assault on enemy trenches, but this technique was soon found to be impractical and the BAR became a conventional light machine gun supporting the infantry.