Trigger (firearms) in the context of "Matchlock"

The hand cannon (simplified Chinese: 火铳; traditional Chinese: 火銃; pinyin: huǒchòng or 手铳; 手銃; shǒuchòng), also known as the gonne or handgonne, is the first true firearm and the successor of the fire lance. It is the oldest type of small arms, as well as the most mechanically simple form of metal barrel firearms. Unlike matchlock firearms it requires direct manual external ignition through a touch hole without any form of firing mechanism. It may also be considered a forerunner of the handgun. The hand cannon was widely used in China from the 13th century onward and later throughout Eurasia in the 14th century. In 15th century Europe, the hand cannon evolved to become the matchlock arquebus, which became the first firearm to have a trigger.

An arquebus (/ˈɑːrk(w)əbəs/ AR-k(w)ə-bəs) is a form of long gun that appeared in Europe and the Ottoman Empire during the 15th century. An infantryman armed with an arquebus is called an arquebusier.

The term arquebus was applied to many different forms of firearms from the 15th to 17th centuries, but it originally referred to "a hand-gun with a hook-like projection or lug on its under surface, useful for steadying it against battlements or other objects when firing". These "hook guns" were in their earliest forms defensive weapons mounted on German city walls in the early 15th century. The addition of a shoulder stock, priming pan, and matchlock mechanism in the late 15th century turned the arquebus into a handheld firearm and also the first firearm equipped with a trigger.

A semi-automatic pistol (also called a self-loading pistol, autopistol, or autoloading pistol) is a repeating handgun that automatically ejects and loads cartridges in its chamber after every shot fired, but only one round of ammunition is fired each time the trigger is pulled. The pistol's fire control group disconnects the trigger mechanism from the firing pin/striker until the trigger has been released and reset manually, unlike the self-cycled firing mechanism in fully automatic pistols.

A semi-automatic pistol recycles part of the energy released by the propellant combustion to move its bolt, which is usually housed inside the slide. After a round of ammunition is fired, the spent cartridge casing is extracted and ejected as the slide/bolt moves rearwards under recoil, the hammer/striker is cocked by the slide/bolt movement, and a new round from the magazine is pushed into the chamber when the slide/bolt returns forward under spring tension. This sets up the following shot (i.e. "in battery"), which is fired as soon as the trigger is pulled again. Most pistols use a short recoil operation to perform this, but some pistols use simple blowback or gas operation mechanisms.

In firearm designs, the term single-shot refers to guns that can hold only a single round of ammunition inside and thus must be reloaded manually after every shot. Compared to multi-shot repeating firearms ("repeaters"), single-shot designs have no moving parts other than the trigger, hammer/firing pin or frizzen, and therefore do not need a sizable receiver behind the barrel to accommodate a moving action, making them far less complex and more robust than revolvers or magazine/belt-fed firearms, but also with much slower rates of fire.

The history of firearms began with muzzleloading single-shot firearms such as the hand cannon and arquebus, then multi-barreled designs such as the derringer appeared, and eventually many centuries passed before breechloading repeating firearms became commonplace. Although largely disappeared from military usage due to insufficient firepower, single-shot firearms are still produced by many manufacturers in both muzzleloading and cartridge-firing varieties, from zip guns and ultra-concealable pocket pistols to the highest-quality hunting and match rifles.

In firearms terminology, an action is the functional mechanism of a breechloading firearm that handles (loads, locks, fires, extracts, and ejects) the ammunition cartridges, or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all those are single-shot firearms with a closed off breech with the powder and projectile manually loaded from the muzzle. Instead, the muzzleloader ignition mechanism is referred to as the lock (e.g. matchlock, wheellock, flintlock, and caplock).

Actions can be categorized in several ways, including single action versus double action, break action versus lever-action, pump-action, bolt-action, among many other types. The term action can also include short, long, and magnum if it is in reference to the length of the rifle's receiver and the length of the bolt. The short action rifle usually can accommodate a cartridge length of 2.8 in (71 mm) or smaller. The long action rifle can accommodate a cartridge of 3.34 in (85 mm), and the magnum action rifle can accommodate cartridges of 3.6 in (91 mm).

Pump action is a type of manual firearm action that is operated by moving a sliding handguard on the gun's forestock. After shooting a round, the sliding handguard is pulled rearward to eject any expended cartridge and typically to cock the hammer or striker, and then pushed forward to load a new cartridge into the chamber. Most pump-action firearms use an integral tubular magazine, although others use detachable box magazines. Pump-action mechanisms are typically found in shotguns, although they also may be found in rifles, grenade launchers, and other types of firearms. A firearm using this operating mechanism is colloquially referred to as a pumpgun.

Because the forend (handguard) is usually manipulated with the support hand, a pump-action firearm can fire additional shots much faster than a bolt-action and somewhat faster than a lever-action, as it does not require the trigger hand to be removed from the trigger while reloading. Also because the action is cycled in a linear fashion, it creates less torque that can tilt and throw the gun off aim when repeat-firing rapidly.

An automatic firearm or fully automatic firearm (to avoid confusion with semi-automatic firearms) is a self-loading 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.

If both the feeding and ignition procedures are automatically cycled, the weapon will be considered "fully automatic" and will fire continuously as long as the trigger is kept depressed and the ammunition feeding (either from a magazine or a belt) remains available. In contrast, a firearm is considered "semi-automatic" if it only automatically cycles to chamber new rounds (i.e. self-loading), but does not automatically fire off the shot unless the user manually resets (usually by releasing) and re-actuates the trigger, so only one round gets discharged with each individual trigger-pull. A burst-fire firearm is an "in-between" of fully and semi-automatic firearms, firing a brief continuous "burst" of multiple rounds with each trigger-pull, but then will require a manual re-actuation of the trigger to fire another burst.

A heat gun is a device used to emit a stream of hot air, usually at temperatures between 100 and 550 °C (373 and 823 K; 212 and 1,022 °F), with some hotter models running around 760 °C (1,030 K; 1,400 °F), which can be held by hand. Heat guns usually have the form of an elongated body pointing at what is to be heated, with a handle fixed to it at right angles and a pistol grip trigger in the same pistol form factor as many other power tools.

Though it shares similarities to a hair dryer, it is not meant as a substitute for the latter, which safely spreads the heat out across its nozzle to prevent scalp burning and has a limited temperature range, while heat guns have a concentrated element and nozzle, along with higher temperatures, which can easily scald the scalp or catch the hair on fire.