Gun
SIG Pro semi-automatic pistol
A gun is a device designed to propel a projectile using pressure or explosive force. The projectiles are typically solid but can also be pressurized liquid (e.g. in water guns/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).
The first devices identified as guns or proto-guns appeared in China from around AD 1000. By the end of the 13th century, they had become "true guns", metal barrel firearms that fired single projectiles which occluded the barrel. Gunpowder and gun technology spread throughout Eurasia during the 14th century.
Pistol
A government-issue M1911 pistol manufactured in 1914
A pistol is a type of handgun, characterised by a barrel with an integral chamber. The word "pistol" derives from the Middle French pistolet (c. 1550), meaning a small gun or knife, and first appeared in the English language c. 1570 when early handguns were produced in Europe. In colloquial usage, the word "pistol" is often used as a generic term to describe any type of handgun, inclusive of revolvers (which have a single barrel and a separate cylinder housing multiple chambers) and the pocket-sized derringers (which are often multi-barrelled).
The most common type of pistol used in the contemporary era is the semi-automatic pistol, while the older single-shot and lever-action pistols are now rarely seen and used primarily for nostalgic hunting and historical reenactment, and the fully-automatic machine pistols are uncommon in civilian usage because of their generally poor recoil-controllability (due to the lack of a buttstock) and strict laws and regulations governing their manufacture and sale (where they are regarded as submachine gun equivalents).
Technically speaking, the term "pistol" is a hypernym generally referring to a handgun and predates the existence of the type of guns to which it is now applied as a specific term; that is, in colloquial usage it is used specifically to describe a handgun with a single integral chamber within its barrel. Webster's Dictionary defines it as "a handgun whose chamber is integral with the barrel". This makes it distinct from the other types of handgun, such as the revolver, which has multiple chambers within a rotating cylinder that is separately aligned with a single barrel; and the derringer, which is a short pocket gun often with multiple single-shot barrels and no reciprocating action. The 18 U.S. Code § 921 legally defines the term "pistol" as "a weapon originally designed, made, and intended to fire a projectile (bullet) from one or more barrels when held in one hand, and having: a chamber(s) as an integral part(s) of, or permanently aligned with, the bore(s); and a short stock designed to be gripped by one hand at an angle to and extending below the line of the bore(s)", which includes derringers but excludes revolvers.
Revolver
Colt Single Action Army
A revolver is a repeating handgun with at least one barrel and a revolving cylinder containing multiple chambers (each holding a single cartridge) for firing. Because most revolver models hold up to six cartridges, before needing to be reloaded, revolvers are commonly called six shooters or sixguns. Due to their rotating cylinder mechanism, they may also be called wheel guns.
Before firing, cocking the revolver's hammer partially rotates the cylinder, indexing one of the cylinder chambers into alignment with the barrel, allowing the bullet to be fired through the bore. By sequentially rotating through each chamber, the revolver allows the user to fire multiple times until having to reload the gun, unlike older single-shot firearms that had to be reloaded after each shot. The hammer cocking in nearly all revolvers is manually driven and can be cocked either by the user using the thumb to directly pull back the hammer (as in single-action), or via internal linkage relaying the force of the trigger-pull (as in double-action), or both (as in double-action/single-action).
Some rare revolver models can utilize the blowback of the preceding shot to automatically cock the hammer and index the next chamber, although these self-loading revolvers (known as automatic revolvers, despite technically being semi-automatic) never gained any widespread usage.
Rifle
Names of parts of the M1 Garand rifle, World War II era, from US Army field manual
A rifle is a long-barreled firearm designed for accurate shooting and higher stopping power, with a barrel that has a helical or spiralling pattern of grooves (rifling) cut into the bore wall.[1][2][3] In keeping with their focus on accuracy,[4] rifles are typically designed to be held with both hands and braced firmly against the shooter's shoulder via a buttstock for stability during shooting. Rifles have been used in warfare, law enforcement, hunting and target shooting sports.
The term was originally rifled gun, with the verb rifle referring to the early modern machining process of creating grooves with cutting tools. By the 20th century, the weapon had become so common that the modern noun rifle is now often used for any log-shaped handheld ranged weapon designed for well-aimed discharge activated by a trigger.
Like all typical firearms, a rifle's projectile (bullet) is propelled by the contained deflagration of a combustible propellant compound (originally black powder and now nitrocellulose and other smokeless powders), although other propulsive means are used, such as compressed air in air rifles, which are popular for vermin control, small game hunting, competitive target shooting and casual sport shooting.
