Semi-automatic firearmA semi-automatic firearm, also called a self-loading or autoloading firearm (fully automatic and selective fire firearms are also variations on self-loading firearms), is a repeating firearm whose action mechanism automatically loads a following round of cartridge into the chamber (self-loading) and prepares it for subsequent firing, but requires the shooter to manually actuate the trigger in order to discharge each shot.
Air gunAn air gun or airgun is a gun that using energy from compressed air or other gases that are mechanically pressurized and released as propellant for the chosen projectiles based on the principle of the primitive blowgun . This is in contrast to a firearm, which fires projectiles using energy by burning combustible propellants, most often gunpowder. Air guns come in both long gun (air rifle) and handgun (air pistol) forms.
Bolt actionBolt-action is a type of manual firearm action that is operated by directly manipulating the bolt via a bolt handle, which is most commonly placed on the right-hand side of the firearm (as most users are right-handed). Most bolt-action firearms use a rotating bolt design, where the handle must first be rotated upward to unlock the bolt from the receiver, then pulled back to open the breech and allowing any spent cartridge case to be extracted and ejected.
Automatic firearmAn automatic firearm or fully automatic firearm (to avoid confusion with semi-automatic firearms) is an autoloading firearm that continuously chambers and fires rounds when the trigger mechanism is actuated. The action of an automatic firearm is capable of harvesting the excess energy released from a previous discharge to feed a new ammunition round into the chamber, and then igniting the propellant and discharging the projectile (either bullet, shot, or slug) by delivering a hammer or striker impact on the primer.
Semi-automatic pistolA semi-automatic pistol (sometimes automatic pistol) is a handgun that automatically ejects and loads cartridges in its chamber after every shot fired. Only one round of ammunition is fired each time the trigger is pulled, as the pistol's fire control group disconnects the trigger mechanism from the firing pin/striker until the trigger has been released and reset. Additional terms sometimes used as synonyms for a semi-automatic pistol are: self-loading pistol, autopistol, autoloading pistol, and automatic pistol.
Machine pistolA machine pistol is an autoloading pistol capable of fully automatic fire. The term can also be used to describe a stockless handgun-style submachine gun. The term is a calque of Maschinenpistole, the German word for submachine guns. Machine pistols were developed during World War I and originally issued to German artillery crews who needed a self-defense weapon that is lighter than a rifle but more powerful than a standard semi-automatic pistol. This concept would eventually lead to the development of the personal defense weapon or PDW.
