Afirearm is any type ofgun that uses anexplosive charge and is designed to be readily carried and operated by an individual.^[1][2][3] The term is legally defined further in different countries (seelegal definitions).

The first firearms originated in 10th-centuryChina, whenbamboo tubes containinggunpowder andpellet projectiles were mounted onspears to make the portablefire lance,^[4] operable by a single person, which was later used effectively as a shock weapon in thesiege of De'an in 1132. In the 13th century, fire lance barrels were replaced with metal tubes and transformed into the metal-barreledhand cannon.^[5] The technology gradually spread throughoutEurasia during the 14th century. Older firearms typically used black powder as apropellant, but modern firearms usesmokeless powder or other explosive propellants. Most modern firearms (with the notable exception ofsmoothboreshotguns) haverifled barrels to impart spin to theprojectile for improved flight stability.

Modern firearms can be described by theircaliber (i.e. bore diameter). For pistols and rifles this is given in millimeters or inches (e.g. 7.62mm or .308 in.); in the case of shotguns,gauge or bore (e.g. 12 ga. or .410 bore.). They are also described by the type of action employed (e.g.muzzleloader,breechloader,lever,bolt,pump,revolver,semi-automatic,fully automatic, etc.), together with the usual means of deportment (i.e. hand-held or mechanical mounting). Further classification may make reference to the type ofbarrel used (i.e.rifled) and to the barrel length (e.g. 24 inches), to the firing mechanism (e.g.matchlock,wheellock,flintlock, orpercussion lock), to the design's primary intended use (e.g.hunting rifle), or to the commonly accepted name for a particular variation (e.g.Gatling gun).

Shooters aim firearms at their targets withhand-eye coordination, using eitheriron sights oroptical sights. The accurate range ofpistols generally does not exceed 100 metres (110 yd; 330 ft), while mostrifles are accurate to 500 metres (550 yd; 1,600 ft) using iron sights, or to longer ranges whilst using optical sights. Purpose-builtsniper rifles andanti-materiel rifles are accurate to ranges of more than 2,000 metres (2,200 yd). (Firearm rounds may be dangerous or lethal well beyond their accurate range; the minimum distance for safety is much greater than the specified range for accuracy.)

A firearm is abarreled weapon that inflicts damage on targets by launching one or moreprojectiles driven by rapidly expanding high-pressure gas produced byexothermic combustion (deflagration) of a chemicalpropellant, historicallyblack powder, nowsmokeless powder.^[1][2][3]

In the military, firearms are categorized intoheavy andlight weapons regarding their portability byinfantry. Light firearms are those that can be readily carried by individualfoot soldier, though they might still require more than one individual (crew-served) to achieve optimal operational capacity. Heavy firearms are those that are too large and heavy to be transported on foot, or too unstable againstrecoil, and thus require the support of aweapons platform (e.g. afixed mount,wheeled carriage,vehicle,aircraft orwater vessel) to be tacticallymobile or useful.

Thesubset of light firearms that only usekinetic projectiles and are compact enough to be operated to full capacity by a single infantryman (individual-served) are also referred to assmall arms. Such firearms includehandguns such aspistols,revolvers, andderringers; andlong guns such asrifles (and their subtypes),shotguns,submachine guns, andmachine guns.^[6]

Among the world'sarms manufacturers, the top firearms manufacturers areBrowning,Remington,Colt,Ruger,Smith & Wesson,Savage,Mossberg (United States),Heckler & Koch,SIG Sauer,Walther (Germany),ČZUB (Czech Republic),Glock,Steyr Arms (Austria),FN Herstal (Belgium),Beretta (Italy),Norinco (China),Rostec, andKalashnikov (Russia). Former top producers included theSpringfield Armory (United States), theRoyal Small Arms Factory (United Kingdom),Mauser (Germany),Steyr-Daimler-Puch (Austria), and Rock Island Armory underArmscor (Philippines).^{[citation needed]}

As of 2018^[update] theSmall Arms Survey reported that there were over one billion firearms distributed globally, of which 857 million (about 85 percent) were incivilian hands.^[7][8] U.S. civilians alone account for 393 million (about 46 percent) of the worldwide total of civilian-held firearms.^[8] This amounts to "120.5 firearms for every 100 residents".^[8] The world'sarmed forces control about 133 million (about 13 percent) of the global total of small arms, of which over 43 percent belong to two countries: theRussian Federation (30.3 million) andChina (27.5 million).^[7]Law enforcement agencies control about 23 million (about 2 percent) of the global total of small arms.^[7]

A handgun is, as defined generally and in manygun laws, a firearm that can be used with a single hand.^{[9][10][11][12]} They are the smallest of all firearms, and are common assidearms,concealed carry weapons, or as backup weapons forself-defense.

Handguns can be categorized into two broad types:pistols, which have a single fixed firing chamber machined into the rear of the barrel, and are often loaded using magazines of varying capacities;revolvers, which have a number of firing chambers or "charge holes" in arevolving cylinder, each one loaded with a singlecartridge or charge; andderringers, broadly defined as any handgun that is not a traditional pistol nor a revolver.

There are various types of the aforementioned handguns designed for different mechanisms or purposes, such assingle-shot,manual repeating,semi-automatic, orautomatic pistols;single-action,double-action, ordouble-action/single-action revolvers; and small, compact handguns for concealed carry such aspocket pistols and "Saturday night specials".

Examples of pistols includeGlocks,Browning Hi-Power,M1911 pistol,Makarov pistol,Walther PP,Luger pistol,Mauser C96, andBeretta 92. Examples of revolvers include theColt Single Action Army,Smith & Wesson Model 10,Colt Official Police,Colt Python,New Nambu M60, andMateba Autorevolver. Examples of derringers include theRemington Model 95,FP-45 Liberator, andCOP .357 Derringer.

A long gun is any firearm with a notably long barrel, typically a length of 10 to 30 inches (250 to 760 mm) (there are restrictions on minimum barrel length in many jurisdictions; maximum barrel length is usually a matter of practicality). Unlike a handgun, long guns are designed to be held and fired with both hands, while braced against either the hip or the shoulder for better stability. The receiver and trigger group is mounted into a stock made of wood, plastic, metal, or composite material, which has sections that form a foregrip, rear grip, and optionally (but typically) a shoulder mount called thebutt. Early long arms, from theRenaissance up to the mid-19th century, were generally smoothbore firearms that fired one or more ball shot, calledmuskets orarquebuses depending on caliber and firing mechanism. Since the 19th and 20th centuries, various types of long guns have been created for different purposes.

A rifle is a long gun that hasriflings (spiral grooves) machined into thebore (inner) surface of its barrel, imparting a gyroscopically stabilizing spin to thebullets that it fires. A descendant of the musket, rifles produce a single point of impact with each firing with a long range and high accuracy. For this reason, as well as for their ubiquity, rifles are very popular among militaries asservice rifles, police as accurate long-range alternatives to their traditionalshotgun long guns, and civilians forhunting,shooting sports, andself-defense.

Many types of rifles exist owing to their wide adoption and versatility, ranging from mere barrel length differences as inshort-barreled rifles andcarbines, to classifications per the rifle's function and purpose as insemi-automatic rifles,automatic rifles andsniper rifles, to differences in the rifle's action as insingle-shot,break-action,bolt-action, andlever-action rifles.

Examples of rifles of various types include theHenry rifle,Winchester rifle,Lee–Enfield,Gewehr 98,M1 Garand,MAS-36 rifle,AKM,Ruger 10/22,Heckler & Koch G3,Remington Model 700, andHeckler & Koch HK417.

A shotgun is a long gun that has a predominantlysmoothbore barrel—meaning it lacks rifling—designed to fire a number ofshot pellets in each discharge. These shot pellet sizes commonly range between 2 mm #9 birdshot and 8.4 mm #00 (double-aught) buckshot, and produce a cluster of impact points with considerably less range and accuracy, sinceshot spreads during flight. Shotguns are also capable of firing single solid projectiles calledslugs, or specialty (often "less lethal") munitions such asbean bags ortear gas to function as ariot gun orbreaching rounds to function as adoor breaching shotgun. Shotgun munitions, regardless of type, are packed intoshotgun shells (cartridges designed specifically for shotguns) that are loaded into the shotgun for use; these shells are commonly loose and manually loaded one-by-one, though some shotguns accept magazines.

Shotguns share many qualities with rifles, such as both being descendants of early long guns such as the musket; both havingsingle-shot,break-action,bolt-action,lever-action,pump-action,semi-automatic, andautomatic variants; and both being popular with militaries, police, and civilians for largely the same reasons. However, unlike rifles, shotguns are less favored in combat roles due to their low accuracy and limited effectiveness inmodern warfare, withcombat shotguns often only used for breaching orclose-quarters combat and sometimes limited to underbarrel attachments such as theM26 Modular Accessory Shotgun System. Shotguns are still popular with civilians for the suitability of their shot spread in hunting,clay pigeon shooting, and home defense.

Double-barreled shotguns are break-action shotguns with two parallel barrels (horizontal side-by-side or vertical over-and-under), allowing two single shots that can be loaded and fired in quick succession.

Examples of shotguns include theWinchester Model 1897,Browning Auto-5,Ithaca 37,Remington Model 870,Mossberg 500,Benelli M4,Franchi SPAS-12,Atchisson AA-12, andKnight's Armament Company Masterkey.

A carbine is a long gun, usually a rifle, that has had its barrel shortened from its original length or is of a certain size smaller than standard rifles, but is still large enough to be considered a long gun. How considerable the difference is between a rifle and a carbine varies; for example, the standardHeckler & Koch G36's barrel has a length of 480 mm (18.9 in), the G36K carbine variant's barrel is 318 mm (12.5 in), and the G36C compact variant's barrel is 228 mm (9.0 in). Some carbines are also redesigned compared to their rifle counterparts, such as the aforementioned G36/G36K and G36C, or theAK-74 andAKS-74U. However, some carbines, such as theM1 carbine, are not a variant of any existing design and are their own firearm model. Carbines are regardless very similar to rifles and often have the same actions (single-shot, lever-action, bolt-action, semi-automatic, automatic, etc.). This similarity has given carbines the alternate name ofshort barreled rifle (SBR), though this more accurately describes a full-size rifle with a shortened carbine-style barrel for close-quarters use.

The small size of a carbine provides lighter weight and better maneuverability, making them ideal forclose-quarters combat and storage in compact areas. This makes them popular firearms amongspecial forces andpolice tactical units alongsidesubmachine guns, considerably so since the late 1990s due to the familiarity and betterstopping power of carbines compared to submachine guns. They are also popular with (and were originally mostly intended for) military personnel in roles that are expected to engage in combat, but where a full-size rifle would be an impediment to the primary duties of that soldier (logistical personnel,airborne forces,military engineers,officers, etc.), though since the turn of the millennium these have been superseded to a degree in some roles bypersonal defense weapons. Carbines are also common among civilian firearm owners who have size, space, and power concerns similar to military and police users.

Examples of carbines include theWinchester Model 1892,Rifle No. 5 Mk I,SKS,M1 carbine,Ruger Mini-14,M4 carbine, andKel-Tec SUB-2000.

An assault rifle is commonly defined as aselective-fire rifle chambered in anintermediate cartridge (such as5.56×45mm NATO,7.62×39mm,5.45×39mm, and.300 AAC Blackout) and fed with a detachablemagazine.^{[13][14][15][16][17]} Assault rifles are also usually smaller than full-sized rifles such asbattle rifles.

Originating with theStG 44 produced byNazi Germany duringWorld War II, assault rifles have since become extremely popular among militaries and other armed groups due to their universal versatility, and they have made up the vast majority of standard-issue militaryservice rifles since the mid-20th century. Various configurations of assault rifle exist, such as thebullpup, in which the firing grip is located in front of thebreech instead of behind it.

Examples of assault rifles include theKalashnikov rifles of Soviet and Russian origin (such as theAK-47,AKM, andAK-74), as well as the AmericanM4 carbine andM16 rifle.

A battle rifle is commonly defined as a semi-automatic or selective-fire rifle that is larger or longer than an assault rifle and is chambered in a "full-power" cartridge (e.g.7.62×51mm NATO,7.92×57mm Mauser,7.62×54mmR). The term originated as aretronym to differentiate older full-powered rifles of these configurations like theM1 Garand, from newer assault rifles usingintermediate cartridges like theHeckler & Koch HK33, but it is sometimes used to describe similar modern rifles such as theFN SCAR.

Battle rifles serve similar purposes as assault rifles, as they both are usually employed by ground infantry for essentially the same purposes. However, some prefer battle rifles for their more powerful cartridge, despite the added recoil. Some designated marksman rifles are configured from battle rifles, such as theMk 14 Enhanced Battle Rifle andUnited States Marine Corps Designated Marksman Rifle, both essentially heavily modified and modernized variants of theM14 rifle.

Examples of rifles considered to be battle rifles include theFG 42,Gewehr 43,FN FAL,Howa Type 64, andDesert Tech MDR.

A sniper rifle is, per widespread definition, a high-powered precision rifle, oftenbolt-action or semi-automatic, with aneffective range farther than that of a standard rifle. Though any rifle in a sniper configuration (usually with atelescopic sight andbipod) can be considered a sniper rifle, most sniper rifles are purpose-built for their applications, or are variants of existing rifles that have been modified to function as sniper rifles, such as theType 97 sniper rifle, which was essentially a standardType 38 rifle that was modified to be lighter and come with a telescopic sight.

Related developments areanti-materiel rifles, large-caliber rifles designed to destroy enemymateriel such as vehicles, supplies, or hardware;anti-tank rifles, anti-materiel rifles that were designed specifically to combat earlyarmoured fighting vehicles, but are now largely obsolete due to advances invehicle armour;scout rifles, a broad class of rifles generally summed up as short, lightweight, portable sniper rifles; anddesignated marksman rifles, semi-automatic high-precision rifles, usually chambered in intermediate or full-power cartridges, that fill the range gap between sniper rifles and regular rifles and are designed fordesignated marksmen in squads.

Examples of sniper and scout rifles include theM40 rifle,Heckler & Koch PSG1,Walther WA 2000,Accuracy International AWM,M24 Sniper Weapon System,Steyr Scout,Sako TRG, andCheyTac Intervention. Examples of anti-materiel and anti-tank rifles include theMauser Tankgewehr M1918,Boys anti-tank rifle,PTRS-41,Barrett M82,Gepárd anti-materiel rifle, andMcMillan TAC-50. Examples of designated marksman rifles include theSVD,SR-25,Dragunov SVU,Marine Scout Sniper Rifle,Mk 14 Enhanced Battle Rifle, andM110 Semi-Automatic Sniper System.

An automatic rifle is a magazine-fed rifle that is capable of automatic fire. They include most assault rifles and battle rifles, but originated as their own category of rifles capable of automatic fire, as opposed to the bolt-action and semi-automatic rifles commonly issued to infantry at the time of their invention. They usually have smaller magazine capacities thanmachine guns; the FrenchChauchat had a 20-round box magazine, while theHotchkiss Mle 1914 machine gun, theFrench Army's standard machine gun at the time, was fed by a 250-roundammunition belt.

Though automatic rifles are sometimes considered to be their own category, they are also occasionally considered to be other types of firearms that postdated their invention, usually aslight machine guns. Automatic rifles are sometimes confused with machine guns or vice versa, or are defined as such by law; theNational Firearms Act andFirearm Owners Protection Act define a "machine gun" inUnited States CodeTitle 26, Subtitle E, Chapter 53, Subchapter B, Part 1, § 5845 as "... any firearm which shoots ... automatically more than one shot, without manual reloading, by a single function of the trigger". "Machine gun" is therefore largely synonymous with "automatic weapon" in American civilian parlance, covering all automatic firearms. In most jurisdictions, automatic rifles, as well as automatic firearms in general, are prohibited from civilian purchase or are at least heavily restricted; in the U.S. for instance, most automatic rifles areTitle II weapons that require certain licenses and are greatly regulated.

Examples of automatic rifles include theCei-Rigotti,Lewis gun,Fedorov Avtomat, andM1918 Browning automatic rifle.

A machine gun is a fully-automatic firearm, chambered in intermediate or full-power rifle cartridges, designed to provide sustained automaticdirect fire as opposed to the semi-automatic orburst fire of standard rifles. They are commonly associated with beingbelt-fed, though many machine guns are also fed by box, drum, pan, or hopper magazines. They generally have a highrate of fire and a large ammunition capacity, and are often used forsuppressive fire to support infantry advances or defend positions from enemy assaults. Owing to their versatility and firepower, they are also commonly installed onmilitary vehicles andmilitary aircraft, either as main or ancillary weapons. Many machine guns are individual-served and can be operated by a single soldier, though some arecrew-served weapons that require a dedicated crew of soldiers to operate, usually between two and six soldiers depending on the machine gun's operation and the crew members' roles (ammunition bearers, spotters, etc.).

Machine guns can be divided into three categories:light machine guns, individual-served machine guns of anintermediate cartridge that are usually magazine-fed;medium machine guns, belt-fed machine guns of a full-power caliber and a certain weight that can be operated by an individual but tend to work best with a crew; andheavy machine guns, machine guns that are too large and heavy to be carried and are thusmounted to something (like atripod ormilitary vehicle), and require a crew to operate. Ageneral-purpose machine gun combines these categories under a single flexible machine gun platform, often one that is most suitable as a light or medium machine gun but fares well as a heavy machine gun. A closely related concept is thesquad automatic weapon, a portable light machine gun or even a modified rifle that is designed and fielded to provide asquad with rapiddirect fire.

Examples of machine guns include theMaxim gun,M2 Browning,Bren light machine gun,MG 42,PK machine gun,FN MAG,M249 light machine gun,RPK,IWI Negev, andM134 Minigun.

A submachine gun is a magazine-fed carbine chambered in a small-caliberhandgun cartridge (such as9×19mm Parabellum,.45 ACP,.22 Long Rifle, and.40 S&W). They cannot be considered machine guns due to their small-caliber, hence the prefix "sub-" to differentiate them from proper machine guns. Submachine guns are commonly associated with high rates of fire, automatic fire capabilities, and low recoil, though many submachine guns differentiate from this in various ways, such as having fairly low rates of fire or including burst and semi-automatic modes available through selective fire. Most submachine guns are the size of carbines and short-barreled rifles, and use similar configurations. Many are designed to take as little space as possible for use in close-quarters or for easy storage in vehicles and cases. Some submachine guns are designed and configured similar to pistols even down to size, and are thus occasionally classed asmachine pistols, even if they are not actually a handgun (i.e. designed to require two hands to use).

Submachine guns are considered ideal forclose-quarters combat and are cheap to mass-produce. They were very common in military service through much of the 20th century, but have since been superseded in most combat roles by rifles, carbines, and personal defense weapons due to their low effective range and poor penetration against mostbody armor developed since the late 20th century. However, they remain popular among special forces and police for their effectiveness in close-quarters and low likelihood tooverpenetrate targets.

Examples of submachine guns include theMP 18,MP 40,Thompson submachine gun,M3 submachine gun,Uzi,Heckler & Koch MP5,Spectre M4,Steyr TMP,Heckler & Koch UMP,PP-2000,KRISS Vector, andSIG MPX.

A personal defense weapon is, in simplest terms, a submachine gun that is designed to fire ammunition with ballistic performance that is similar to (but not actually a type of) rifle cartridges, often called "sub-intermediate" cartridges. In this way, it combines the high automatic rate of fire, reliable low recoil, and lightweight compact maneuverability of submachine guns with the versatility, penetration, and effective range of rifles, effectively making them an "in-between" of submachine guns and carbines.

Personal defense weapons were developed to providerear and "second-line" personnel not otherwise armed with high-caliber firearms (vehicle and weapon crews, engineers, logistical personnel, etc.) with a method of effective self-defense againstskirmishers andinfiltrators who cannot effectively be defeated by low-powered submachine guns and handguns, often the only firearms suitable for those personnel (while they could be issued rifles or carbines, those would become unnecessary burdens in their normal duties, during which the likelihood of hostility is fairly rare regardless, making their issuance questionable). Thus, per their name, personal defense weapons allow these personnel to effectively defend themselves from enemies and repel attacks themselves or at least until support can arrive. They are not intended for civilian self-defense due to their nature as automatic firearms (which are usually prohibited from civilian purchase), though some semi-automatic PDWs exist for the civilian market, albeit often with longer barrels.

Examples of personal defense weapons include theFN P90,Heckler & Koch MP7,AAC Honey Badger, andST Kinetics CPW.

Types aside, firearms are also categorized by their "action", which describes their loading, firing, and unloading cycle.

Manual action ormanual operation is essentially any type of firearm action that is loaded, and usually also fired, one cartridge at a time by the user, rather than automatically. Manual action firearms can be divided into two basic categories:single-shot firearms that can only be fired once per barrel before it must be reloaded or charged via an external mechanism or series of steps; andrepeating firearms that can be fired multiple times per barrel, but can only be fired once with each subsequent pull of the trigger or ignite, and the firearm's action must be reloaded or charged via an internal mechanism between trigger pulls.

Types of manual actions include lever action, bolt action, and pump action.

Lever action is a repeating action that is operated by using acocking handle (the "lever") located around thetrigger guard area (often incorporating it) that is pulled down then back up to move thebolt via internallinkages and cock thefiring pin mechanism, expelling the oldcartridge and loading a new one.

Bolt action is a repeating (and rarely single-shot) action that is operated by directly manipulating the bolt via abolt handle. The bolt is unlocked from thereceiver, then pulled back to open thebreech, ejecting a cartridge, and cocking thestriker and engaging it against thesear; when the bolt is returned to the forward position, a new cartridge, if loaded, is pushed out of the magazine and into the barrelchamber, and the breech is re-locked.

Two designs of bolt action exist:rotating bolt, where the bolt must be axially rotated to unlock and lock the receiver; andstraight pull, which does not require the bolt to be rotated, simplifying the bolt action mechanism and allowing for a greater rate of fire.

Pump action orslide action is a repeating action that is operated by moving a slidinghandguard (the "pump") on the gun'sforestock rearward (frontward on some models), ejecting any spent cartridges and cocking thehammer or striker, then moving the handguard forward to load a new cartridge into the chamber.^[18] It is most common on shotguns, though pump action rifles and grenade launchers also exist.

Semi-automatic,self-loading, orautoloading is a firearm action that, after a single discharge, automatically performs the feeding and ignition procedures necessary to prepare the firearm for a subsequent discharge. Semi-automatic firearms only discharge once with each trigger actuation, and the trigger must be actuated again to fire another cartridge.

Types of semi-automatic actions and modes include automatic, burst, and selective.

Automatic is a firearm action that uses the same automated action cycling as semi-automatic, but continues to do so for as long as the trigger is actuated, until the trigger is let go of or the firearm is depleted of available ammunition. The excess energy released from a discharged cartridge is used to load a new cartridge into the chamber, then igniting thepropellant and discharging said new cartridge by delivering a hammer or striker impact on theprimer. Automatic firearms are further defined by the type ofcycling principles used, such asrecoil operation (uses energy from therecoil to cycle the action),blowback (uses energy from the cartridge case as it is pushed by expanding gas),blow forward (use propellant gas pressure to open the breech), orgas operation (uses high-pressure gas from a fired cartridge to dispose of the spent case and load a new cartridge).

Burst is a fire mode of some semi-automatic and automatic firearms that fires a predetermined amount of rounds—usually two or three—in the same manner as automatic fire. Depending on the firearm, a single trigger actuation may fire the full burst of rounds, or it must be depressed for the entire discharge, with a single pull of the trigger firing a single round or an incomplete burst. Most firearms with burst capabilities have it as a fire mode secondary to semi-automatic and automatic.

Selective fire orselect fire is the capability of a firearm to have its fire mode adjusted between semi-automatic, burst, or automatic. The modes are chosen by means of afire mode selector, which varies depending on the weapon's design. The presence of selective-fire modes on firearms allows more efficient use of ammunition for specific tactical needs, either precision-aimed orsuppressive fire. Selective fire is most commonly found on assault rifles and submachine guns.

Firearms can be used asblunt weapons, for instance to conserve limited ammunition or whenammunition has run out entirely.^[19]

New recruits of theIsrael Defense Forces undergo training on the safe practice of using the M16 rifle as a blunt weapon, mainly so that in close-quarter fighting, the weapon cannot be pulled away from them. Other training includes the recruit learning how to jab parts of the body with themuzzle and using thebutt stock as a weapon.^{[citation needed]}

Forensic medicine recognizes evidence for various types ofblunt-force injuries produced by firearms. For example, "pistol-whipping" typically leaves semicircular or triangular lacerations of skin produced by the butt of a pistol.^[20]

In armed robberies, beating the victims with firearms is a more common way to complete the robbery, rather than shooting or stabbing them.^[21]

Examples include:

• Buttstroking, striking with thebutt stock of a firearm.^[22]
• Pistol-whipping, striking someone with ahandgun.^[23]
• Striking with themuzzle end of a firearm without abayonet attached.^[24]

The first firearms were invented in 10th centuryChina when the man-portablefire lance (a bamboo or metal tube that could shoot ignitedgunpowder) was combined with projectiles such as scrap metal, broken porcelain, or darts/arrows.^[4][25]

An early depiction of a firearm is a sculpture from a cave inSichuan, China. The sculpture dates to the 12th century^[26] and represents a figure carrying a vase-shapedbombard, with flames and acannonball coming out of it.^[27] The oldest surviving gun, ahand cannon made of bronze, has been dated to 1288 because it was discovered at a site in modern-dayAcheng District,Heilongjiang, China, where theYuan Shi records that battles were fought at that time.^[28] The firearm had a 17.5 cm (6.9 in) barrel of a 2.5 cm (1 in) diameter, a 6.6 cm (2.6 in) chamber for the gunpowder and a socket for the firearm's handle. It is 34 centimetres (13 in) long and 3.54 kilograms (7.8 lb) without the handle, which would have been made of wood.^[29]

The Arabs andMamluks had firearms in the late-13th century.^[30][31][32] Europeans obtained firearms in the 14th century.^[33] The Koreans adopted firearms from the Chinese in the 14th century. The Iranians (firstAq Qoyunlu andSafavids) and Indians (firstMughals) all got them no later than the 15th century, from the Ottoman Turks. The people of theNusantara archipelago of Southeast Asia used thelong arquebus at least by the last quarter of the 15th century.^[34]: 23

Even though the knowledge of making gunpowder-based weapons in theNusantara archipelago had been known after the failedMongol invasion of Java (1293), and the predecessor of firearms, thepole gun (bedil tombak), was recorded as being used by Java in 1413,^{[35][36]: 245} the knowledge of making "true" firearms came much later, after the middle of 15th century. It was brought by theIslamic nations of West Asia, most probably theArabs. The precise year of introduction is unknown, but it may be safely concluded to be no earlier than 1460.^[34]: 23 Before the arrival of the Portuguese in Southeast Asia, the natives already possessed firearms, theJava arquebus.^[37]

The technology of firearms inSoutheast Asia further improved after thePortuguese capture of Malacca (1511).^[38] Starting in the 1513, the traditions of German-Bohemian gun-making merged with Turkish gun-making traditions.^{[39]: 39–41} This resulted in the Indo-Portuguese tradition of matchlocks. Indian craftsmen modified the design by introducing a very short, almost pistol-like buttstock held against the cheek, not the shoulder, when aiming. They also reduced the caliber and made the gun lighter and more balanced. This was a hit with the Portuguese who did a lot of fighting aboard ship and on river craft, and valued a more compact gun.^{[40]: 41 [41]} TheMalaccan gunfounders,^{[check spelling]} compared as being in the same level with those of Germany, quickly adapted these new firearms, and thus a new type of arquebus, theistinggar, appeared.^[42]: 385 The Japanese did not acquire firearms until the 16th century, and then from the Portuguese rather than from the Chinese.^[27]

Developments in firearms accelerated during the 19th and 20th centuries. Breech-loading became more or less a universal standard for the reloading of most hand-held firearms and continues to be so with some notable exceptions (such as mortars). Instead of loading individual rounds into weapons, magazines holding multiple munitions were adopted—these aided rapid reloading. Automatic and semi-automatic firing mechanisms meant that a single soldier could fire many more rounds in a minute than a vintage weapon could fire over the course of a battle. Polymers and alloys in firearm construction made weaponry progressively lighter and thus easier to deploy. Ammunition changed over the centuries from simple metallic ball-shaped projectiles that rattled down the barrel to bullets and cartridges manufactured to high precision. Especially in the past century^[timeframe?] particular attention has focused on accuracy and sighting to make firearms altogether far more accurate than ever before. More than any single factor though, firearms have proliferated due to the advent of mass production—enabling arms-manufacturers to produce large quantities of weaponry to a consistent standard.^{[citation needed]}

Velocities of bullets increased with the use of a "jacket" of metals such as copper or copper alloys that covered a lead core and allowed the bullet to glide down the barrel more easily than exposed lead. Such bullets are known as "full metal jacket" (FMJ). Such FMJ bullets are less likely to fragment on impact and are more likely to traverse through a target while imparting less energy. Hence, FMJ bullets impart less tissue damage than non-jacketed bullets that expand.^[43] This led to their adoption for military use by countries adhering to theHague Convention of 1899.^[44]

That said, the basic principle behind firearm operation remains unchanged to this day. A musket of several centuries ago is still similar in principle to a modern-day rifle—using the expansion of gases to propel projectiles over long distances—albeit less accurately and rapidly.^[45]

The Chinesefire lance from the 10th century was the direct predecessor to the modern concept of the firearm. It was not a gun itself, but an addition to soldiers' spears. Originally it consisted of paper or bamboo barrels that would contain incendiary gunpowder that could be lit one time and which would project flames at the enemy. Sometimes Chinese troops would place small projectiles within the barrel that would also be projected when the gunpowder was lit, but most of the explosive force would create flames. Later, the barrel was changed to be made of metal, so that more explosive gunpowder could be used and put more force into the propulsion of projectiles.^{[46]: 31–32}

The original predecessor of all firearms, the Chinesehand cannon from the 13th century, was loaded with gunpowder and the projectile (initiallylead shot, later replaced by cast iron^{[citation needed]}) through the muzzle, while a fuse was placed at the rear. This fuse was lit, causing the gunpowder to ignite and propel the projectiles. In military use, the Chinese hand cannon was tremendously powerful, while also being somewhat erratic^{[citation needed]} due to the relative inability of the gunner to aim the weapon, or to control the ballistic properties of the projectile. Recoil could be absorbed by bracing the barrel against the ground using a wooden support, the forerunner of thestock. Neither the quality nor amount of gunpowder, nor the consistency in projectile dimensions was controlled, with resulting inaccuracy in firing due towindage, variance in gunpowder composition, and the difference in diameter between thebore and the shot. Hand cannons were replaced around the 15th century by lighter carriage-mountedartillery pieces, and ultimately by thearquebus.

In the 1420s, gunpowder was used to propel missiles from hand-held tubes duringthe Hussite revolt in Bohemia.^{[47][unreliable source?]}

Thearquebus is a long gun that appeared in Europe and theOttoman Empire during the 15th Century. The termarquebus is derived from the Dutch wordhaaqbus (literally meaninghook gun). The term arquebus was applied to many different types of guns. In their earliest form they were defensive weapon mounts on German city walls in the 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 first firearm equipped with a trigger. Heavy arquebuses mounted onwar wagons were calledarquebus a croc. These heavy arquebuses fired alead ball of about 3.5 ounces (100g).

Muzzle-loading muskets (smooth-bored long guns) were among the first firearms developed.^[when?] The firearm was loaded through the muzzle with gunpowder, optionally with some wadding, and then with a bullet (usually a solid lead ball, but musketeers could shoot stones when they ran out of bullets). Greatly improved muzzleloaders (usually rifled instead of smooth-bored) are manufactured today and have many enthusiasts, many of whom hunt large and small game with their guns. Muzzleloaders have to be manually reloaded after each shot; a skilled archer could fire multiple arrows faster than most early muskets could be reloaded and fired, although by the mid-18th century when muzzleloaders became the standard small-armament of the military, a well-drilled soldier could fire six rounds in a minute using prepared cartridges in his musket. Before then, the effectiveness of muzzleloaders was hindered both by the low reloading speed and, before the firing mechanism was perfected, by the very high risk posed by the firearm to the person attempting to fire it.^{[citation needed]}

One interesting solution to the reloading problem was the "Roman Candle Gun" withsuperposed loads. This was a muzzleloader in which multiple charges and balls were loaded one on top of the other, with a small hole in each ball to allow the subsequent charge to be ignited after the one ahead of it was ignited. It was neither a very reliable nor popular firearm, but it enabled a form of "automatic" fire long before the advent of the machine gun.^[48]

Matchlocks were the first and simplest firearms-firing mechanisms developed. In the matchlock mechanism, the powder in the gun barrel was ignited by a piece of burning cord called a "match". The match was wedged into one end of an S-shaped piece of steel. When the trigger (often actually a lever) was pulled, the match was brought into the open end of a "touch hole" at the base of the gun barrel, which contained a very small quantity of gunpowder, igniting the main charge of gunpowder in the gun barrel. The match usually had to be relit after each firing. The main parts of the matchlock firing mechanism are the pan, match, arm, and trigger.^[49] A benefit of the pan and arm swivel being moved to the side of the gun was it gave a clear line of fire.^[50] An advantage to the matchlock firing mechanism is that it did not misfire. However, it also came with some disadvantages. One disadvantage involved weather: in rain, the match could not be kept lit to fire the weapon. Another issue with the match was it could give away the position of soldiers because of the glow, sound, and smell.^[51] While European pistols were equipped with wheellock and flintlock mechanisms, Asian pistols used^[when?] matchlock mechanisms.^[52]

Thewheellock action, a successor to the matchlock, predated the flintlock. Despite its many faults, the wheellock was a significant improvement over the matchlock in terms of both convenience and safety, since it eliminated the need to keep a smoldering match in proximity to loose gunpowder. It operated using a small wheel (much like that on acigarette lighter) which was wound up with a key before use and which, when the trigger was pulled, spun against a flint, creating the shower of sparks that ignited the powder in the touch hole. Supposedly invented byLeonardo da Vinci (1452–1519), the ItalianRenaissance man, the wheellock action was an innovation that was not widely adopted due to the high cost of the clockwork mechanism.

Theflintlock action represented a major innovation in firearm design. The spark used to ignite the gunpowder in the touch hole came from a sharpened piece of flint clamped in the jaws of a "cock" which, when released by the trigger, struck a piece of steel called the "frizzen" to generate the necessary sparks. (The spring-loaded arm that holds a piece of flint or pyrite is referred to as a cock because of its resemblance to a rooster.) The cock had to be manually reset after each firing, and the flint had to be replaced periodically due to wear from striking the frizzen. (See alsoflintlock mechanism,snaphance,Miquelet lock.) The flintlock was widely used during the 17th, 18th, and 19th centuries in both muskets and rifles.

Percussion caps (caplock mechanisms), coming into wide service in the early 19th century, offered a dramatic improvement over flintlocks. With the percussion-cap mechanism, the small primer charge of gunpowder used in all preceding firearms was replaced by a completely self-contained explosive charge contained in a small brass "cap". The cap was fastened to the touch hole of the gun (extended to form a "nipple") and ignited by the impact of the gun's "hammer". (The hammer is roughly the same as the cock found on flintlocks except that it does not clamp onto anything.) In the case of percussion caps the hammer was hollow on the end to fit around the cap in order to keep the cap from fragmenting and injuring the shooter.

Once struck, the flame from the cap, in turn, ignited the main charge of gunpowder, as with the flintlock, but there was no longer any need to charge the touch hole with gunpowder, and even better, the touch hole was no longer exposed to the elements. As a result, the percussion-cap mechanism was considerably safer, far more weatherproof, and vastly more reliable (cloth-bound cartridges containing a pre-measured charge of gunpowder and a ball had been in regular military service for many years, but the exposed gunpowder in the entry to the touch hole had long been a source of misfires). Allmuzzleloaders manufactured since the second half of the 19th-century use percussion caps except those built as replicas of the flintlock or earlier firearms.

Most early firearms were muzzle-loading. This form of loading has several disadvantages, such as a slow rate of fire and having to expose oneself to enemy fire to reload—as the weapon had to be pointed upright so the powder could be poured through the muzzle into the breech, followed by the ramming the projectile into the breech. As effective methods of sealing the breech developed along with sturdy, weatherproof, self-contained metallic cartridges, muzzle-loaders were replaced by single-shot breech loaders. Eventually, single-shot weapons were replaced by the following repeater-type weapons.

Many firearms made from the late-19th century through the 1950s used internal magazines to load the cartridge into the chamber of the weapon. The most notable and revolutionary weapons of this period appeared during the U.S. Civil War of 1861–1865: theSpencer andHenry repeating rifles. Both used fixed tubular magazines, the former having the magazine in the buttstock and the latter under the barrel, which allowed a larger capacity. Later weapons used fixed box magazines that could not be removed from the weapon without disassembling the weapon itself. Fixed magazines permitted the use of larger cartridges and eliminated the hazard of having the bullet of one cartridge butting next to the primer or rim of another cartridge. These magazines are loaded while they are in the weapon, often using a stripper clip. A clip is used to transfer cartridges into the magazine. Some notable weapons that use internal magazines include theMosin–Nagant, theMauser Kar 98k, theSpringfield M1903, theM1 Garand, and theSKS. Firearms that have internal magazines are usually, but not always, rifles. Some exceptions to this include the Mauser C96 pistol, which uses an internal magazine, and theBreda 30, an Italian light machine gun.

Many modern firearms use what are called detachable or box magazines as their method of chambering a cartridge. Detachable magazines can be removed from the weapon without disassembling the firearms, usually by pushing a magazine release.

A belt or ammunition belt, a device used to retain and feed cartridges into a firearm, is commonly used with machine guns. Belts were originally composed of canvas or cloth with pockets spaced evenly to allow the belt to be mechanically fed into the gun. These designs were prone to malfunctions due to the effects of oil and other contaminants altering the belt. Later belt-designs used permanently-connected metal links to retain the cartridges during feeding. These belts were more tolerant to exposure to solvents and oil. Notable weapons that use belts include the M240, the M249, the M134 Minigun, and the PK Machine Gun.

FrenchmanLouis-Nicolas Flobert invented the firstrimfire metallic cartridge in 1845. His cartridge consisted of a percussion cap with a bullet attached to the top.^[53][54] Flobert then made what he called "parlor guns" for this cartridge, as these rifles and pistols were designed to be shot in indoor shooting-parlors in large homes.^[55][56] These6mm Flobert cartridges do not contain any powder, the onlypropellant substance contained in the cartridge is the percussion cap.^[57] In English-speaking countries, the 6mm Flobert cartridge corresponds to.22 BB Cap and.22 CB Cap ammunition. These cartridges have a relatively low muzzle-velocity of around 700 ft/s (210 m/s).

Cartridges represented a major innovation: firearms ammunition, previously delivered as separate bullets and powder, was combined in a single metallic (usually brass)cartridge containing a percussion cap, powder, and a bullet in one weatherproof package. The main technical advantage of the brass cartridge case was the effective and reliable sealing of high-pressure gasses at the breech, as the gas pressure forces the cartridge case to expand outward, pressing it firmly against the inside of the gun-barrel chamber. This prevents the leakage of hot gas which could injure the shooter. The brass cartridge also opened the way for modern repeating arms, by uniting the bullet, gunpowder, and primer into one assembly that could be fed reliably into the breech by mechanical action in the firearm.

Before this, a "cartridge" was simply a pre-measured quantity ofgunpowder together with a ball in a small cloth bag (or rolled paper cylinder), which also acted aswadding for the charge and ball. This early form of cartridge had to be rammed into the muzzleloader's barrel, and either a small charge of gunpowder in the touch hole or an external percussion cap mounted on the touch hole ignited the gunpowder in the cartridge. Cartridges with built-in percussion caps (called "primers") continue to this day to be the standard in firearms. In cartridge-firing firearms, a hammer (or a firing pin struck by the hammer) strikes the cartridge primer, which then ignites the gunpowder within. The primer charge is at the base of the cartridge, either within the rim (a"rimfire" cartridge) or in a small percussion cap embedded in the center of the base (a "centerfire" cartridge). As a rule, centerfire cartridges are more powerful than rimfire cartridges, operating at considerably higher pressures than rimfire cartridges. Centerfire cartridges are also safer, as a dropped rimfire cartridge has the potential to discharge if its rim strikes the ground with sufficient force to ignite the primer. This is practically impossible with most centerfire cartridges.

Nearly all contemporary firearms load cartridges directly into theirbreech. Some additionally or exclusively load from amagazine that holds multiple cartridges. A magazine is a part of the firearm which exists to store ammunition and to assist in its feeding by the action into the breech (such as through the rotation of a revolver's cylinder or by spring-loaded platforms in most pistol and rifle designs). Some magazines, such as that of most centerfire hunting rifles and all revolvers, are internal to and inseparable from the firearm, and are loaded by using a "clip". Aclip (the term often mistakenly refers to a detachable "magazine") is a device that holds the ammunition by the rim of the case and is designed to assist the shooter in reloading the firearm's magazine. Examples include revolverspeedloaders, thestripper clip used to aid loading rifles such as theLee–Enfield orMauser 98, and theen-bloc clip used in loading theM1 Garand. In this sense, "magazines" and "clips", though often used synonymously, refer to different types of devices.

Many firearms are "single shot": i.e., each time a cartridge is fired, the operator must manually re-cock the firearm and load another cartridge. The classic single-barreled shotgun offers a good example. A firearm that can load multiple cartridges as the firearm is re-cocked is considered a "repeating firearm" or simply a "repeater". A lever-action rifle, a pump-action shotgun, and most bolt-action rifles are good examples of repeating firearms. A firearm that automatically re-cocks and reloads the next round with each trigger-pull is considered a semi-automatic or autoloading firearm.

The first "rapid firing" firearms were usually similar to the 19th-centuryGatling gun, which would fire cartridges from a magazine as fast as and as long as the operator turned a crank. Eventually, the "rapid" firing mechanism was perfected and miniaturized to the extent that either the recoil of the firearm or the gas pressure from firing could be used to operate it, thus the operator needed only to pull a trigger—this made the firing mechanisms truly "automatic". Anautomatic (or "fully automatic") firearm automatically re-cocks, reloads, and fires as long as the trigger is depressed. An automatic firearm is capable of firing multiple rounds with one pull of the trigger. TheGatling gun may have been the first automatic weapon, though the modern trigger-actuated machine gun was not widely introduced until theFirst World War (1914–1918) with the German"Spandau" (adopted in 1908) and the BritishLewis gun (in service from 1914). Automatic rifles such as theBrowning automatic rifle were in common use by the military during the early part of the 20th century, and automatic rifles that fired handgun rounds, known as submachine guns, also appeared at this time. Many modern military firearms have aselective fire option, which is a mechanical switch that allows the firearm to be fired either in the semi-automatic or fully automatic mode. In the current M16A2 and M16A4 variants of the U.S.-madeM16, continuous fully-automatic fire is not possible, having been replaced by an automatic burst of three cartridges (this conserves ammunition and increases controllability).

Firearm hazard is quite notable, with a significant impact on the health system. In 2001, for quantification purposes, it was estimated that the cost of fatalities and injuries was US$4700 million per year in Canada (US$170 per Canadian) and US$100,000 million per year in the U.S. (US$300 per American).^[58]

From 1990 to 2015, global deaths from assault by firearm rose from 128,000 to 173,000,^[60][61] however this represents a drop in rate from 2.41/100,000 to 2.35/100,000, as world population has increased by more than two billion.^[62]

In 2017, there were 39,773 gun-related deaths in the United States; over 60% were suicides from firearms.^[63] In 2001, firearms were involved in cases constituting the second leading cause of "mechanism of injury deaths" (which are deaths which occur as a direct, identifiable, and immediate consequence of an event, such as a shooting or poisoning, and do not include deaths due to "natural causes" or "indirect causes" such as chronic alcohol abuse or tobacco use) aftermotor vehicle accidents, which comprised the majority of deaths in this category.^[64][65] The most recent, complete data, from 2017, shows gunshot related homicides as having been the 31st most common cause of death in the US, while gunshot related suicides was the 21st most common cause of death. Accidental discharge of a firearm accounted for the 59th most common cause of death, with 486 deaths in 2017, while 616 individuals were killed by law enforcement, comprising the 58th most common cause of death. The total number of deaths related to firearms in 2017 was 38,882 (not including incidents of deaths resulting from lethal force when used by law enforcement), while the most common cause of death, heart disease, claimed 647,457 lives, over sixteen times that of firearms, including suicides. The most recent data from the CDC, from 2020, shows that deaths involving firearms accounted for about 0.2% of all deaths nationwide in 2020, of which about two-thirds were suicides.^[66][67]

In the 52 high- and middle-income countries, with a combined population of 1,400 million and not engaged in civil conflict, fatalities due to firearm injuries were estimated at 115,000 people per annum, in the 1990s.^[58]

In those 52 countries, a firearm is the first method used for homicide (two-thirds) but only the second method for suicide (20%.^[58]

To prevent unintentional injury, gun safety training includes education on proper firearm storage and firearm-handling etiquette.^[68][69]

Based on US data, it is estimated that three people are injured for one killed.^[58]

A 2017 study found that attacks account for more than half (50.2%) of all nonfatal gun injuries, while unintentional injuries make up more than one-third (36.7%).^[70]

PTSD or Post-traumatic stress disorder is extremely prevalent in the aftermath of different firearm-related events, such as mass shootings, injuries, and police-involved incidents. In particular, military Veterans are especially at high risk for the development of PTSD. In 2004, Hoge et al. found that soldiers that fought in Iraq or Afghanistan who significantly engaged in firefights had a linear association with the risk of PTSD. Hoge found that the rates of PTSD ranged from 4.5% from those who had not been involved in firefights to 19.3% to those involved in five or more firefights, displaying an apparent correlation between risk of PTSD and firefights.^[71] Additionally, school shootings are often studied and exhibit a connection between PTSD and the involvement with firearms. It was found that rates of PTSD were highest in students that were in direct exposure, which was around 9.7% of the recorded population. Rates would be as low as 3.4% in those with no exposure.^[72]

Many bullets used with firearms are made of lead. If lead reaches the bloodstream, which can occur when handling ammunition, it can lead to kidney damage and issues with brain development. Extremely high levels can lead to seizures, unconsciousness, and even death.^[73]

A common hazard of repeated firearm use isnoise-induced hearing loss (NIHL). NIHL can result from long-term exposure to noise or from high intensity impact noises such as gunshots.^[74][75] Individuals who shoot guns often have a characteristic pattern of hearing loss referred to as "shooters ear". They often have a high-frequency loss with better hearing in the low frequencies and one ear is typically worse than the other. The ear on the side the shooter is holding the gun will receive protection from the sound wave from the shoulder while the other ear remains unprotected and more susceptible to the full impact of the sound wave.^[75][76]

The intensity of a gunshot does vary; lower caliber guns are typically on the softer side while higher caliber guns are often louder. The intensity of a gunshot though typically ranges from 140 dB to 175 dB. Indoor shooting also causes loud reverberations which can also be as damaging as the actual gunshot itself.^[75][76] According to the National Institute on Deafness and Other Communication Disorders, noise above 85 dB can begin to cause hearing loss.^[74] While many sounds cause damage over time, at the intensity level of a gunshot (140 dB or louder), damage to the ear can occur instantly.^[74][76]

Shooters use custom hearing protection such as electronic type hearing protection for hunters which can amplify soft sounds like leaves crunching while reducing the intensity of the gunshot and custom hearing protection for skeet shooting.^[75][76]

Even with hearing protection, due to the high intensity of the noise guns produce shooters still develop hearing loss over time.^[75]

Firearms include a variety of ranged weapons and there is no agreed-upon definition. For instance, English language laws of big legal entities such as the United States, India, the European Union and Canada use different definitions. Other English language definitions are provided by international treaties.

In theUnited States, under 26 USC § 5845 (a), the term "firearm" means

• (1) a shotgun having a barrel or barrels of less than 18 inches in length;
• (2) a weapon made from a shotgun if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 18 inches in length;
• (3) a rifle having a barrel or barrels of less than 16 inches in length;
• (4) a weapon made from a rifle if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length;
• (5) any other weapon, as defined in subsection (e);
• (6) a machinegun;
• (7) any silencer (as defined in section 921 of title 18, United States Code);
  The term "firearm" shall not include an antique firearm or any device (other than a machinegun or destructive device) which, although designed as a weapon, the Secretary finds by reason of the date of its manufacture, value, design, and other characteristics is primarily a collector's item and is not likely to be used as a weapon.

This is the ATF definition of atitle II "NFA firearm", as defined by theNational Firearms Act, and not the definition of a title I firearm, which includes firearms not restricted by the NFA. ATF forms dealing with Title II weapons all state the above-mentioned information, however, the above information is only applicable for the purposes of those forms. For practical purposes, a firearm, in the U.S., is defined as the part of a weapon- designed to use expanded gas caused by the combustion of explosive material, to propel a projectile- which houses the fire control group (trigger & sear).

According to the U.S.Bureau of Alcohol, Tobacco, Firearms and Explosives, if gas pressurization is achieved throughmechanicalgas compression rather than through chemical propellant combustion, then the device is technically anair gun, not a firearm.^[77]

In India, the arms act, 1959, provides a definition of firearms where "firearms" means arms of any description designed or adapted to discharge a projectile or projectiles of any kind by the action of any explosive or other forms of energy, and includes:

• (i) artillery, hand-grenades, riot-pistols or weapons of any kind designed or adapted for the discharge of any noxious liquid, gas, or other such thing,
• (ii) accessories for any such firearm designed or adapted to diminish the noise or flash caused by the firing thereof,
• (iii) parts of, and machinery for manufacturing, fire-arms, and
• (iv) carriages, platforms, and appliances for mounting, transporting and serving artillery;

In the European Union, aEuropean Directive amended by EU directive 2017/853 set minimum standards regarding civilian firearms acquisition and possession that EU member states must implement into their national legal systems. In this context, since 2017, firearms are considered as "any portable barrelled weapon that expels, is designed to expel or may be converted to expel a shot, bullet or projectile by the action of a combustible propellant".^[78] For legal reasons, objects can be considered a firearm if they have the appearance of a firearm or are made in a way that makes it possible to convert them to a firearm. Member states may be allowed to exclude from their gun control law items such as antique weapons, or specific purposes items that can only be used for that sole purpose.

In the UK, a firearm does not have to use a combustible propellant, as explained byCrown Prosecution Service Guidance Firearms The Firearms Act 1968 Section 57(1B), uses the definition of a firearm as a "lethal barrelled weapon" as a "barrelled weapon of any description from which a shot, bullet or other missile, with kinetic energy of more than one joule as measured at the muzzle of the weapon, can be discharged". As such, low-energy air rifles and pistols also fall under UK firearm legislation, although the licensing requirements of low-energy weapons are more relaxed.

In Canada, firearms are defined by the Criminal Code:

firearm means a barrelled weapon from which any shot, bullet, or other projectile can be discharged and that is capable of causing serious bodily injury or death to a person, and includes any frame or receiver of such a barrelled weapon and anything that can be adapted for use as a firearm; (arme à feu)^[79]

Australia has a definition of firearms in its 1996 legal act:

"firearm" means any device, whether or not assembled or in parts —

• (a) which is designed or adapted, or is capable of being modified, to discharge shot or a bullet or other missile by the expansion of gases produced in the device by the ignition of strongly combustible materials or by compressed air or other gases, whether stored in the device in pressurised containers or produced in the device by mechanical means; and
• (b) whether or not operable or complete or temporarily or permanently inoperable or incomplete

— and which is not —

• (c) an industrial tool powered by cartridges containing gunpowder or compressed air or other gases which is designed and intended for use for fixing fasteners or plugs or for similar purposes; or
• (d) a captive bolt humane killer; or
• (e) a spear gun designed for underwater use; or
• (f) a device designed for the discharge of signal flares; or
• (h) a device commonly known as a kiln gun or ringblaster, designed specifically for knocking out or down solid material in kilns, furnaces or cement silos; or
• (i) a device commonly known as a line thrower designed for establishing lines between structures or natural features and powered by compressed air to other compressed gases and used for rescue purposes, rescue training or rescue demonstration; or
• (j) a device of a prescribed class;^[10]

In South Africa, Firearms Control Act [No. 60 of 2000] defines firearms since June 2001, with a 2006 amendment of the definition:

'firearm' means any-

• (a) device manufactured or designed to propel a bullet or projectile through a barrel or cylinder by means of burning propellant, at a muzzle energy exceeding 8 joules (6 ft-lbs);
• (b) device manufactured or designed to discharge rim-fire, centre-fire or pin-fire ammunition;
• (c) device which is not at the time capable of discharging any bullet or projectile, but which can be readily altered to be a firearm within the meaning of paragraph (a) or (b);
• (d) device manufactured to discharge a bullet or any other projectile of a calibre of 5.6 mm (.22 calibre) or higher at a muzzle energy of more than 8 joules (6 ft-lbs), by means of compressed gas and not by means of burning propellant; or [Para. (d) substituted by s. 1 (b) of Act 43 of 2003.]
• (e) barrel, frame or receiver of a device referred to in paragraphs (a), (b), (c) or (d), but does not include a muzzle loading firearm or any device contemplated in section 5;^[9]

An inter-American convention defines firearms as:

• any barreled weapon which will or is designed to or may be readily converted to expel a bullet or projectile by the action of an explosive, except antique firearms manufactured before the 20th Century or their replicas; or
• any other weapon or destructive device such as any explosive, incendiary or gas bomb, grenade, rocket, rocket launcher, missile, missile system, or mine.^[80]

Aninternational UN protocol on firearms considers that

"Firearm" shall mean any portable barrelled weapon that expels, is designed to expel or may be readily converted to expel a shot, bullet or projectile by the action of an explosive, excluding antique firearms or their replicas. Antique firearms and their replicas shall be defined in accordance with domestic law. In no case, however, shall antique firearms include firearms manufactured after 1899^[81]

• Andrade, Tonio (2016).The Gunpowder Age: China, Military Innovation, and the Rise of the West in World History. Princeton University Press.ISBN 978-0-691-13597-7..
• Chase, Kenneth (2003).Firearms: A Global History to 1700. Cambridge University Press.ISBN 978-0-521-82274-9.
• Cole, Suzanne N. (2017).Association of Firearm Instructors Glossary of Firearm Terms: 2017–2018 Edition. United States: The Association of Firearm Instructors.ISBN 978-0-9982150-3-7.
• Crosby, Alfred W. (2002).Throwing Fire: Projectile Technology Through History. Cambridge University Press.ISBN 978-0-521-79158-8.
• Needham, Joseph (1986).Science & Civilisation in China. Vol. 7The Gunpowder Epic. Cambridge University Press.ISBN 978-0-521-30358-3.

•   Media related toFirearms at Wikimedia Commons