An automatic weapon is a ranged weapon (be it a fictional directed-energy weapon or real-life firearm) that fires more than one shot when the user pulls the trigger. A fully automatic weapon can fire indefinitely on a single trigger pull, stopping only when its mechanism jams or it runs out of ammunition.
The first fully automatic weapon was developed by Hiram Stevens Maxim in 1884. The advent of automatic weapons had a major effect on tactics, rendering massed charges obsolete, as was demonstrated at the Battle of Omdurman in 1889, in which ten British Maxims decimated over 15,000 cavalrymen. Later, during the Great War, small numbers of machine gun emplacements were able to fend off tens of thousands of soldiers. In the first half of the 20th century, automatic weapons were minaturized to serve as basic infantry weapons, starting with the development of submachine gun (the German MP-18 being the first) and eventually to the development of the assault rifle.