The slide on the majority of fully/

semi-automatic pistol A semi-automatic pistol is a type of repeating single-chamber handgun ( pistol) that automatically cycles its action to insert the subsequent cartridge into the chamber (self-loading), but requires manual actuation of the trigger to actu ...

s is the upper part that reciprocates ("slides") with

recoil Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, as according to Newton's third law the force r ...

during the gun's operating cycle. It serves as the bolt carrier group (BCG) and partly as the receiver, and generally houses the firing pin/ striker, the extractor and frequently also the

barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...

, and provides a mounting platform for

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...

and

optical sight A sight is an aiming device used to assist in visually aligning ranged weapons, surveying instruments or optical illumination equipments with the intended target. Sights can be a simple set or system of physical markers that have to be aligne ...

s. Through the principles of short recoil or simple blowback operations, the slide is moved backwards with each shot by the energy of expanding gasses caused by the combusting

propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the ...

(often a

nitrocellulose Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...

-based

smokeless powder Finnish smokeless powderSmokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to gunpowder ("black powder"). The combustion products are mainly gaseous, compared t ...

, very rarely

black powder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). T ...

). Because the slide is

spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a h ...

-loaded, once at the rearmost position, the spring tension will push it back towards the front. Generally, this slide movement cycle serves three functions: the extractor will empty the

chamber Chamber or the chamber may refer to: In government and organizations *Chamber of commerce, an organization of business owners to promote commercial interests *Legislative chamber, in politics *Debate chamber, the space or room that houses deliber ...

by pulling out the spent casing from the previous shot (which then gets removed out of the gun by the

ejector An injector is a system of ducting and nozzles used to direct the flow of a high-pressure fluid in such a way that a lower pressure fluid is entrained in the jet and carried through a duct to a region of higher pressure. It is a fluid-dynamic ...

), the slide

inertia Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...

will cock the

hammer A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nails into wood, to shape metal (as wi ...

/ striker to prepare for the next shot, and the bolt will push a new cartridge from the

magazine A magazine is a periodical publication, generally published on a regular schedule (often weekly or monthly), containing a variety of content. They are generally financed by advertising, purchase price, prepaid subscriptions, or by a combinatio ...

into the chamber when the slide comes back forward. This action cycle will be repeated for continued firing as long as the magazine contains rounds and there is no failure to extract/ eject (which causes stovepiping and double-feeding), failure to feed, or out-of-battery malfunction. Fully/semi-automatic air pistols' slides operate with similar principles as

firearm A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions). The first firearms originated in 10th-century China, when bamboo tubes ...

s, except they utilize

pneumatic Pneumatics (from Greek ‘wind, breath’) is a branch of engineering that makes use of gas or pressurized air. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and ...

energy from compressed gas (usually air, ,

propane Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as ...

refrigerant A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated ...

s) instead of burning propellants. Because air pistols typically have much lower

muzzle energy Muzzle energy is the kinetic energy of a bullet as it is expelled from the muzzle of a firearm. Without consideration of factors such as aerodynamics and gravity for the sake of comparison, muzzle energy is used as a rough indication of the de ...

than firearms, there is less recoil that can be used to operate the slide. However, because airgun pellets/ shots have no casings that needed to be extracted (unlike firearm cartridges), a very brief slide movement is sufficient to cycle the action and load the subsequent shot, so only a small amount of energy is needed to move the slide. On most modern designs, once the

is empty, a slide stop will catch and lock the slide at its rearmost position, and will only be released to move back forward after the slide release is depressed. Having the slide automatically loading the chamber and cocking the hammer/striker with each prior shot is essential for the function of

double-action Double action (or double-action) refers to one of two systems in firearms where the trigger both cocks and releases the hammer. *Double-action only (DAO) firearms trigger: The trigger both cocks and releases the hammer. There is no single-action f ...

single-action A trigger is a mechanism that actuates the function of a ranged weapon such as a firearm, airgun, crossbow, or speargun. The word may also be used to describe a switch that initiates the operation of other non-shooting devices such as a tra ...

pistols.

Hammerless A hammerless firearm is a firearm that lacks an exposed hammer (firearm), hammer or hammer spur. Although it may not literally lack a hammer, it lacks a hammer that the user can pull directly. One of the disadvantages of an exposed hammer spur i ...

and

striker-fired A firing pin or striker is a part of the firing mechanism of a firearm that impacts the primer in the base of a cartridge and causes it to fire. In firearms terminology, a striker is a particular type of firing pin where a compressed spring ...

pistols, lacking external hammer that can be directly manipulated, need to have the whole slide manually pulled back to cock the hammer/striker if the gun is not already cocked for firing.

See also