semi automatic

A semi-automatic pistol is a type of pistol that is semi-automatic, meaning it uses the energy of the fired cartridge to cycle the action of the firearm and advance the next available cartridge into position for firing. One cartridge is fired each time the trigger of a semi-automatic pistol is pulled; the pistol's "disconnector" ensures this behavior.
Additional terms sometimes used as synonyms for a semi-automatic pistol are automatic pistol, self-loading pistol, autopistol, and autoloading pistol.
A semi-automatic pistol harnesses the energy of one shot to reload the chamber for the next. After a round is fired, the spent casing is ejected and a new round from the magazine is loaded into the chamber, allowing another shot to be fired as soon as the trigger is pulled again. Most pistols use recoil operation to do this, but some pistols use blowback or gas operation.
Most types of semi-automatic pistols rely on a removable magazine to store ammunition before it is fired, usually inserted inside the grip.

View More On Wikipedia.org