A firearm is any type of gun that shoots projectiles using high explosive pressure generated from combustion (deflagration) of chemical propellant, most often black powder in antique firearms and smokeless powder in modern firearms. Small arms is a subset of light firearms that is designed to be readily carried and operated by an individual. The term "firearm" is however variably defined both technically and legally in different countries (see legal definitions), and can be used colloquially (sometimes incorrectly) to refer to any type of guns including air guns.
The first firearms originated in 10th-century Song dynasty China (see gunpowder weapons in the Song dynasty), when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears to make the portable fire lance, which was operable by a single person and was later used effectively as a shock weapon in the siege of De'an in 1132. In the 13th century, fire lance barrels were replaced with metal tubes and transformed into the metal-barreled hand cannon, and the technology gradually spread throughout Eurasia during the 14th century, but there is little information regarding how this spread occurred. Older firearms typically used black powder as a propellant. Beginning in the 1860s, black powder was gradually replaced by smokeless powder, which is mostly based on nitrocellulose. In contrast to black powder, it produces almost entirely gas upon combustion, earning it the title "smokeless powder." Most modern firearms (with the notable exception of smoothbore shotguns) have rifled barrels to impart a stabilizing spin to the bullet for improved external ballistics.
Modern firearms can be described by their caliber (i.e. bore diameter). For handguns 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 (single-shot vs. repeating, e.g. muzzleloader, breechloader, lever, bolt, pump, revolver, semi-automatic, fully automatic, etc.), together with the usual means of deportment (i.e. handheld or mounted). Further classification may make reference to the type of barrel bore used (i.e. rifled vs smoothbore) and to the barrel length (e.g. 24 inches), to the firing mechanism (e.g. matchlock, flintlock, wheellock, caplock or primer-ignited such as needlefire, pinfire, teat-fire, rimfire and centerfire, as well as the atypical electronic firing), to the design's primary intended use (e.g. hunting rifle, service rifle), or to the commonly accepted name for a particular variation (e.g. Gatling gun).
Shooters aim firearms at their targets with hand-eye coordination, using either iron sights or optical sights such as scope, red dot or holographic sights. The effective range of handguns and shotguns generally does not exceed , while most rifles are accurate to using iron sights, or to longer ranges whilst using optical sights. Purpose-built sniper rifles and anti-materiel rifles are accurate to ranges of more than . 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.
Types
A firearm is a barreled weapon that inflicts damage on targets by launching one or more projectiles driven by rapidly expanding high-pressure gas produced by exothermic combustion (deflagration) of a chemical propellant, historically black powder, now smokeless powder.
In the military, firearms are categorized into heavy and light weapons by their portability. Light firearms are those that can be readily carried by individual foot soldier, though they might require more than one individual (i.e. 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 against recoil, and thus require the support of a weapons platform (e.g. a fixed mount, wheeled carriage, vehicle, aircraft or water vessel) to be tactically mobile or useful.
The subset of light firearms that only use kinetic projectiles and are compact enough to be operated to full capacity by a single infantryman (individual-served) are also referred to as small arms. Such firearms include handguns such as pistols, revolvers, and derringers; and long guns such as rifles (and their subtypes), shotguns, submachine guns, and light machine guns.
Among the world's arms manufacturers, the latest data from 2023 released by the Bureau of Alcohol, Tobacco, Firearms, and Explosives shows the top 30 firearms manufacturers in the United States are (in order of number of firearms manufactured): Ruger, SIG Sauer, Smith & Wesson, Savage Arms, Palmetto State Armory, Henry, Mossberg, Glock, Anderson Manufacturing (acquired by Ruger in 2025), Springfield Armory, Aero Precision, Heritage Manufacturing (owned by Taurus), Colt, KelTec, Kimber, FN, Beretta, Remington, Diamondback Firearms, Radical Firearms, Legacy Sports International, SCCY Firearms, Taurus, North American Arms, American Tactical, Shadow Systems, Browning, Daniel Defense, Wilson Combat, and Staccato 2011. Some of the world's largest firearm manufacturers outside the United States include Glock (Austria), Heckler & Koch (Germany), SIG Sauer (Germany/Switzerland), CZ (Czech Republic), Beretta (Italy), FN (Belgium), Taurus (Brazil), Norinco (China), Steyr Arms (Austria), Kalashnikov (Russia), Tokarev (Russia), and Miroku (Japan).
the Small Arms Survey reported that there were over one billion firearms distributed globally, of which 857 million (about 85 percent) were in civilian hands. U.S. civilians alone account for 393 million (about 46 percent) of the worldwide total of civilian-held firearms, as of 2026 the number of civilian-held firearms is estimated to be as much as 500 million. This amounts to "120.5 firearms for every 100 residents", which increased to 150 guns per 100 residents by 2026. The world's armed forces control about 133 million (about 13 percent) of the global total of small arms, of which over 43 percent belong to two countries: the Russian Federation (30.3 million) and China (27.5 million). Law enforcement agencies control about 23 million (about 2 percent) of the global total of small arms.
Handguns
A handgun is, as defined generally and in many gun laws, a firearm that can be used with a single hand. They are the smallest of all firearms, and are common as sidearms, concealed carry weapons, or as backup weapons for self-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 a revolving cylinder, each one loaded with a single cartridge or charge; and derringers, broadly defined as any handgun that is not a traditional pistol nor a revolver, typically they are a small, pocket-sized pistol designed for easy concealment, featuring one or two barrels without a repeating mechanism being loaded either via the muzzle or breech.
There are various types of the aforementioned handguns designed for different mechanisms or purposes, such as single-shot, manual repeating, semi-automatic, or automatic pistols; single-action, double-action, or double-action/single-action revolvers; and small, compact handguns for concealed carry such as pocket pistols and "Saturday night specials".
Examples of pistols include Glocks, Browning Hi-Power, M1911 pistol, Makarov pistol, Walther PP, Luger pistol, Mauser C96, and Beretta 92. Examples of revolvers include the Colt Single Action Army, Smith & Wesson Model 10, Colt Official Police, Colt Python, New Nambu M60, and Mateba Autorevolver. Examples of derringers include the Remington Model 95, FP-45 Liberator, and COP .357 Derringer.
Long guns
A long gun is any firearm with a notably long barrel, typically a length of (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 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 the butt. Early long arms, from the Renaissance up to the mid-19th century, were generally smoothbore firearms that fired one or more ball shot, called muskets or arquebuses depending on caliber and firing mechanism. Since the 19th and 20th centuries, various types of long guns have been created for different purposes.
Rifles
A rifle is a long gun that has riflings (spiral grooves) machined into the bore (inner) surface of its barrel, imparting a gyroscopically stabilizing spin to the bullets 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 as service rifles, police as accurate long-range alternatives to their traditional shotgun long guns, and civilians for hunting, shooting sports, and self-defense.
Many types of rifles exist owing to their wide adoption and versatility, ranging from mere barrel length differences as in short-barreled rifles and carbines, to classifications per the rifle's function and purpose as in semi-automatic rifles, automatic rifles and sniper rifles, to differences in the rifle's action as in falling block, rolling block, single-shot, break-action, bolt-action, and lever-action rifles.
Examples of rifles of various types include the Henry rifle, Winchester Model 94, Winchester Model 70, Lee–Enfield, Gewehr 98, M1 Garand, AK-type, AR-15, Ruger 10/22, Ruger M77, Ruger Mini-14, Heckler & Koch G3, Remington Model 700, Remington Model 7600, and Heckler & Koch HK417.
Shotguns
A shotgun is a long gun that has a predominantly smoothbore barrel—meaning it lacks rifling—designed to fire a number of shot 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 compared to a rifle, since shot spreads during flight. Shotguns are also capable of firing single solid projectiles called slugs (typically used for hunting large animals), or specialty (often "less lethal") munitions such as bean bags or tear gas to function as a riot gun, or breaching rounds to function as a door breaching shotgun. Shotgun munitions, regardless of type, are packed into shotgun 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 having single-shot, break-action, bolt-action, lever-action, pump-action, semi-automatic, and automatic variants; and both being popular with military, 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 in modern warfare, with combat shotguns often only used for breaching, or close-quarters combat situations like jungle warfare, trench warfare, or clearing buildings during urban warfare; for versatility underbarrel attachments such as the M26 Modular Accessory Shotgun System are popular in the military, as they allow a soldier to wield a shotgun and an assault rifle simultaneously. Shotguns are still popular with civilians for the suitability of their shot spread in hunting, clay pigeon shooting, and home defense.