The Probert Encyclopaedia of Warfare

SEMI-AUTOMATIC

A semi-automatic firearm is designed to fire a single cartridge, eject the empty case and reload the chamber each time the trigger is pulled. There are various types of semi-automatic operation, one of the most common being 'blowback' in which gases from the discharged cartridge are channelled to operate the firearm mechanism to discharge the spent cartridge case, reload another from the magazine or belt, and cock the weapon ready for the next pull of the trigger.
Research Semi-automatic