A semi-automatic, or self-loading, firearm is one that performs all steps necessary to prepare it to discharge again after firing—assuming cartridges remain in the firearm's feed device. Typically, this includes extracting and ejecting the spent cartridge case from the firing chamber, re-cocking the firing mechanism, and loading a new cartridge into the firing chamber. Although machine guns and selective-fire firearms do the same tasks, semi-automatic firearms do not automatically fire an additional round until the trigger is released and re-pressed by the person discharging it. That is, a semi-automatic firearm fires only one round (bullet) each time the trigger is pulled.