Firearm in the context of Shooting games

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, charcoal (which is mostly carbon), and potassium nitrate (saltpeter). The sulfur and charcoal act as fuels, while the saltpeter is an oxidizer. Gunpowder has been widely used as a propellant in firearms, artillery, rocketry, and pyrotechnics, including use as a blasting agent for explosives in quarrying, mining, building pipelines, tunnels, and roads.

Gunpowder is classified as a low explosive because of its relatively slow decomposition rate, low ignition temperature and consequently low brisance (breaking/shattering). Low explosives deflagrate—burning at subsonic speeds—whereas high explosives detonate, producing a supersonic shockwave. Ignition of gunpowder packed behind a projectile generates enough pressure to force the shot from the muzzle at high speed, but usually not enough force to rupture the gun barrel. It thus makes a good propellant but is less suitable for shattering rock or fortifications with its low-yield explosive power. Nonetheless, it was widely used to fill fused artillery shells (and used in mining and civil engineering projects) until the second half of the 19th century, when the first high explosives were put into use.

A weapon, arm, or armament is any implement or device that is used to deter, threaten, inflict physical damage, harm, or kill. Weapons are used to increase the efficacy and efficiency of activities such as hunting, crime (e.g., murder), law enforcement, self-defense, warfare, or suicide. In a broader context, weapons may be construed to include anything used to gain a tactical, strategic, material, or mental advantage over an adversary or enemy target.

While ordinary objects such as rocks and bottles can be used as weapons, many objects are expressly designed for the purpose; these range from simple implements such as clubs and swords to complicated modern firearms, tanks, missiles and biological weapons. Something that has been repurposed, converted, or enhanced to become a weapon of war is termed weaponized, such as a weaponized virus or weaponized laser.

A muzzleloader is any firearm in which the user loads the projectile and the propellant charge into the muzzle end of the gun (i.e., from the forward, open end of the gun's barrel). This is distinct from the modern designs of breech-loading firearms, in which user loads the ammunition into the breech end of the barrel. The term "muzzleloader" applies to both rifled and smoothbore type muzzleloaders, and may also refer to the marksman who specializes in the shooting of such firearms. The firing methods, paraphernalia and mechanism further divide both categories as do caliber (from cannons to small-caliber palm guns).

Modern muzzleloading firearms range from reproductions of sidelock, flintlock and percussion long guns, to in-line rifles that use modern inventions such as a closed breech, sealed primer and fast rifling to allow for considerable accuracy at long ranges.

Volley fire, as a military tactic, is (in its simplest form) the concept of having soldiers shoot in the same direction en masse. In practice, it often consists of having a line of soldiers all discharge their weapons simultaneously at the enemy forces on command, known as "firing a volley", followed by more lines of soldiers repeating the same manoeuvre in turns. This is usually to compensate for the inaccuracy, slow rate of fire (as many early ranged weapons took a long time and much effort to reload), limited effective range and stopping power of individual weapons, which often requires a massed saturation attack to be effective. The volley fire, specifically the musketry volley technique (also known as the countermarch), requires lines of soldiers to step to the front, fire on command and then march back into a column to reload, while the next row repeats the same process.

The term "volley" came from Middle French volée, substantivation of the verb voler, which in turns came from Latin volare, both meaning "to fly", referring to the pre-firearm practice of archers mass-shooting into the air to shower their enemy with arrows. While the tactic of volley fire is usually associated with Dutch military thinkers in the late 16th century, its principles have been applied to crossbow infantry since at least the Chinese Tang dynasty.

Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to black powder. Because of their similar use, both the original black powder formulation and the smokeless propellant which replaced it are commonly described as gunpowder. The combustion products of smokeless powder are mainly gaseous, compared to around 55% solid products (mostly potassium carbonate, potassium sulfate, and potassium sulfide) for black powder. In addition, smokeless powder does not leave the thick, heavy fouling of hygroscopic material associated with black powder that causes rusting of the barrel.

Despite its name, smokeless powder is not completely free of smoke; while there may be little noticeable smoke from small-arms ammunition, smoke from artillery fire can be substantial.

Artillery consists of ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and led to heavy, fairly immobile siege engines. As technology improved, lighter, more mobile field artillery cannons were developed for battlefield use. This development continues today; modern self-propelled artillery vehicles are highly mobile weapons of great versatility generally providing the largest share of an army's total firepower.

Originally, the word "artillery" referred to any group of soldiers primarily armed with some form of manufactured weapon or armour. Since the introduction of gunpowder and cannon, "artillery" has largely meant cannon, and in contemporary usage, usually refers to shell-firing guns, howitzers, and mortars (collectively called barrel artillery, cannon artillery or gun artillery) and rocket artillery. In common speech, the word "artillery" is often used to refer to individual devices, along with their accessories and fittings, although these assemblages are more properly called "equipment". However, there is no generally recognized generic term for a gun, howitzer, mortar, and so forth: the United States uses "artillery piece", but most English-speaking armies use "gun" and "mortar". The projectiles fired are typically either "shot" (if solid) or "shell" (if not solid). Historically, variants of solid shot including canister, chain shot and grapeshot were also used. "Shell" is a widely used generic term for a projectile, which is a component of munitions.

A gun barrel is a crucial part of gun-type weapons such as small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end (muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its calibre, usually measured in inches or millimetres.

The first firearms were made at a time when metallurgy was not advanced enough to cast tubes capable of withstanding the explosive forces of early cannons, so the pipe (often built from staves of metal) needed to be braced periodically along its length for structural reinforcement, producing an appearance somewhat reminiscent of storage barrels being stacked together, hence the English name.

The bow and arrow is a ranged weapon system consisting of an elastic launching device (bow) and long-shafted projectiles (arrows). Humans used bows and arrows for hunting and aggression long before recorded history, and the practice was common to many prehistoric cultures. They were important weapons of war from ancient history until the early modern period, when they were rendered increasingly obsolete by the development of the more powerful and accurate firearms. Today, bows and arrows are mostly used for hunting and sports.

Archery is the art, practice, or skill of using bows to shoot arrows. A person who shoots arrows with a bow is called a bowman or an archer. Someone who makes bows is known as a bowyer, someone who makes arrows is a fletcher, and someone who manufactures metal arrowheads is an arrowsmith.

Forensic science, often confused with criminalistics, is the application of science principles and methods to support decision-making related to rules or law, generally specifically criminal and civil law.

During criminal investigation in particular, it is governed by the legal standards of admissible evidence and criminal procedure. It is a broad field utilizing numerous practices such as the analysis of DNA, fingerprints, bloodstain patterns, firearms, ballistics, toxicology, microscopy, and fire debris analysis.

The arms industry, also known as the defense (or defence) industry or military industry is a global industry which manufactures and sells weapons and other military technology to a variety of customers, including the armed forces of states and civilian individuals and organizations. Products of the arms industry include weapons, munitions, weapons platforms, communications systems, and other electronics, and related equipment. The arms industry also provides defense-related services, such as logistical and operational support. As a matter of policy, many governments of industrialized countries maintain or support a network of organizations, facilities, and resources to produce weapons and equipment for their military forces (and sometimes those of other countries). This is often referred to as a defense industrial base. Entities involved in arms production for military purposes vary widely, and include private sector commercial firms, state-owned enterprises and public sector organizations, and scientific and academic institutions. Such entities perform a wide variety of functions, including research and development, engineering, production, and servicing of military material, equipment, and facilities. The weapons they produce are often made, maintained, and stored in arsenals.

In some regions of the world, there is a substantial legal trade in firearms for use by individuals (commonly cited purposes include self-defense and hunting/sporting). Illegal small arms trade occurs in many countries and regions affected by political instability.

The putting-out system, also known historically as the domestic system or workshop system, was a method of subcontracting production in which a central agent, often a merchant or manufacturer, distributed raw materials to workers who completed the work in their own homes or small workshops. This system was widely used in pre-industrial Europe and early America, particularly in the textile industry, shoemaking, lock-making, and the production of small firearm parts. It flourished from the late Middle Ages through the Industrial Revolution, gradually declining in the mid-19th century with the rise of centralized factory production.

Unlike modern concepts of freelancing, subcontracting, or remote work, which are associated with flexible labor markets, digital communication, and individual entrepreneurship, the putting-out system was embedded in the socio-economic structures of agrarian and early-industrial societies. For most workers, it was not a voluntary or entrepreneurial choice but a necessary means of supplementing family income. The system was particularly suited to pre-urban rural economies, where travel to centralized workplaces was impractical, and households combined production tasks with agricultural and domestic chores.

Shooting sports are a group of competitive and recreational sporting activities which focus on shooting accuracy, precision and speed. Shooting is the art of using ranged weapons, mainly firearms and airguns, such as handguns, rifles and shotguns, and also bows/crossbows.

Shooting sports can be categorized by equipment, shooting distance, targets, time limits and the degree of athleticism involved. Shooting sports may involve both team and individual competitions, and team performance is usually assessed by summing the scores of the individual team members. Due to the noise and high impact energy of the projectiles, which can be lethal, shooting sports are typically conducted at either designated permanent shooting ranges or temporary shooting fields in areas away from human settlements.

Heavy infantry consisted of heavily armed and armoured infantrymen who were trained to mount frontal assaults and/or anchor the defensive center of a battle line. This differentiated them from light infantry who were relatively mobile and lightly armoured skirmisher troops intended for screening, scouting, and other tactical roles unsuited to soldiers carrying heavier loads. Heavy infantry typically made use of dense battlefield formations, such as shield wall or phalanx, multiplying their effective weight of arms with force concentration.

Heavy infantry were critical to many ancient armies, which first attested by the Sumerians in the Stele of the Vultures. It was also used by rival Assyrian and Persian Sparabara, then by Greek hoplites, Macedonian phalangites, and Roman legionaries. After the fall of Rome, heavy infantry declined in Europe but returned to dominance in the Late Middle Ages with Swiss pikemen and German Landsknechts. With the rise of firearms during early modern warfare, dense formations became increasingly infeasible, and heavy armours were either ineffective or too cumbersome to be tactically useful. By the early 18th century, heavy infantry were replaced by line infantry armed with muskets and bayonets and wearing little to no armour.

Early modern warfare is the era of warfare during early modern period following medieval warfare. It is associated with the start of the widespread use of gunpowder and the development of suitable weapons to use the explosive, including artillery and firearms; for this reason the era is also referred to as the age of gunpowder warfare (a concept introduced by Michael Roberts in the 1950s).

Fortification techniques evolved rapidly due to the development of artillery. Firearms revolutionized warfare, diminishing the role of aristocracies and heavy cavalry. Early firearms, like arquebuses and muskets, gradually replaced bows and crossbows, leading to the introduction and decline of plate armor as firearms became more effective. Flintlock muskets became dominant by the 1690s, and the invention of the bayonet combined pikes and muskets, transforming infantry into the most crucial military force. Warfare also saw a shift towards larger armies and more devastating conflicts. The rise of centralized states and bureaucracies supported the new, massive armies, while the use of mercenaries declined. Military formations adapted to these changes. Infantry relied on columns, lines, and squares for battle, while cavalry transitioned to lighter roles focused on scouting and flanking. Despite the decline in heavy cavalry's dominance, cavalry charges remained effective under specific conditions, particularly against undisciplined infantry. The Age of Sail (usually dated as 1571–1862) was a period roughly corresponding to the early modern period and gunpowder dominated the era's naval tactics, including the use of gunpowder in naval artillery.

A shotgun (also known as a scattergun, peppergun, or historically as a fowling piece) is a long-barreled firearm designed to shoot a straight-walled cartridge known as a shotshell, which discharges numerous small spherical projectiles called shot, or a single solid projectile called a slug. Shotguns are most commonly used as smoothbore firearms, meaning that their gun barrels have no rifling on the inner wall, but rifled barrels for shooting sabot slugs (slug barrels) are also available.

Shotguns come in a wide variety of calibers and gauges ranging from 5.5 mm (.22 inch) to up to 5 cm (2.0 in), though the 12-gauge (18.53 mm or 0.729 in) and 20-gauge (15.63 mm or 0.615 in) bores are by far the most common. Almost all are breechloading, and can be single barreled, double barreled, or in the form of a combination gun. Like rifles, shotguns also come in a range of different action types, both single-shot and repeating. For non-repeating designs, over-and-under and side-by-side break action shotguns are by far the most common variants. Although revolving shotguns do exist, most modern repeating shotguns are either pump action or semi-automatic, and also fully automatic, lever-action, or bolt-action to a lesser extent.

A gun is a device that propels a projectile using pressure or explosive force. The projectiles are typically solid, but can also be pressurized liquid (e.g. in water guns or cannons), or gas (e.g. light-gas gun). Solid projectiles may be free-flying (as with bullets and artillery shells) or tethered (as with Tasers, spearguns and harpoon guns). A large-caliber gun is also called a cannon. Guns were designed as weapons for military use, and then found use in hunting. Now, there are guns, e.g., toy guns, water guns, paintball guns, etc., for many purposes.

The means of projectile propulsion vary according to designs, but are traditionally effected pneumatically by a high gas pressure contained within a barrel tube (gun barrel), produced either through the rapid exothermic combustion of propellants (as with firearms), or by mechanical compression (as with air guns). The high-pressure gas is introduced behind the projectile, pushing and accelerating it down the length of the tube, imparting sufficient launch velocity to sustain its further travel towards the target once the propelling gas ceases acting upon it after it exits the muzzle. Alternatively, new-concept linear motor weapons may employ an electromagnetic field to achieve acceleration, in which case the barrel may be substituted by guide rails (as in railguns) or wrapped with magnetic coils (as in coilguns).

Liberalism in the United States is based on concepts of unalienable rights of the individual. The fundamental liberal ideals of consent of the governed, freedom of speech, freedom of the press, freedom of religion, the separation of church and state, the right to bear arms, the right to due process, and equality before the law are widely accepted as a common foundation of liberalism. It differs from liberalism worldwide because the United States never had a resident hereditary aristocracy, and avoided much of the class warfare that characterized Europe. According to American philosopher Ian Adams, "all US parties are liberal and always have been", they generally promote classical liberalism, which is "a form of democratized Whig constitutionalism plus the free market", and the "point of difference comes with the influence of social liberalism" and principled disagreements about the proper role of government.

Since the 1930s, liberalism is usually used without a qualifier in the United States to refer to modern liberalism, a variety of liberalism that accepts a government role to prevent market failures and promotes expansion of civil and political rights, with the common good considered as compatible with or superior to the absolute freedom of the individual. This political philosophy was exemplified by Franklin D. Roosevelt's New Deal policies and later Lyndon B. Johnson's Great Society. Other accomplishments include the Works Progress Administration and the Social Security Act in 1935, as well as the Civil Rights Act of 1964 and the Voting Rights Act of 1965. This variety of liberalism is also known as modern liberalism to distinguish it from classical liberalism, from which it sprang out along with modern American conservatism.