What is GUN

In military parlance, a gun is a muzzle or breech-loaded projectile-firing weapon. There are various definitions depending on the nation and branch of service. A "gun" may be distinguished from other firearms in being a crew served weapon such as a howitzer or mortar, as opposed to a small arm like a rifle or pistol, but there are exceptions, such as the USAF's GUU5/P. At one time, land based artillery tubes were called cannon and sea-based naval cannon were called guns. The term "gun" morphed into a generic term for any tube launched projectile firing weapon used by sailors including boarding parties and marines.

In modern parlance, a gun is a projectile weapon using a hollow, tubular barrel with a closed end—the breech—as the means of directing the projectile (as well as other purposes, for example stabilizing the projectile's trajectory, aiming, as an expansion chamber for propellant, etc), and firing in a generally flat trajectory.

The term "gun" has also taken on a more generic meaning, by which it has come to refer to any one of a number of trigger-initiated, hand-held, and hand-directed implements, especially with an extending bore, which thereby resemble the class of weapon in either form or concept. Examples of this usage include staple gun, nail gun, glue gun, grease gun. Occasionally, this tendency is ironically reversed, such as the case of the American M3 submachine gun which carries the nickname "Grease Gun".

Barrel types include rifled—a series of spiraled grooves or angles within the barrel—when the projectile requires an induced spin to stabilize it and smoothbore when the projectile is stabilized by other means or is undesired or unnecessary. Typically, interior barrel diameter and the associated projectile size is a means to identify gun variations. Barrel diameter is reported in several ways. The more conventional measure is reporting the interior diameter of the barrel in decimal fractions of the inch or in millimeters. Some guns—such as shotguns—report the weapon's gauge or—as in some British ordnance—the weight of the weapon's usual projectile.

Types of guns

Military firearms

Long gun

Arquebus

Blunderbuss

Musket

Musketoon

Wall gun

Grenade launcher

Submachine gun

Personal defense weapon

Rifle

Lever action rifle

Bolt action rifle

Assault rifle

Battle rifle

Carbine

Service rifle

Sniper rifle

Shotgun

Combat shotgun

Semi-automatic shotgun

Automatic shotgun

Machine guns

Gatling gun

Minigun

Nordenfelt gun

Metal storm

Mitrailleuse

Submachine gun

Machine pistol

Machine gun

General-purpose machine gun

Light machine gun

Squad automatic weapon

Infantry Automatic Rifle

Medium machine gun

Heavy machine gun

M134 Minigun

Handguns

Handgun

Pistol

Service pistol

Revolver

Service revolver

Machine pistol

Autocannon

Autocannon

Chain gun

Artillery guns

Artillery gun

Cannon

Carronade

Falconet

Field gun

Howitzer

Tank guns

Tank gun

Hunting guns

Elephant gun

Express rifle

Shotgun

Muzzleloader

Breechloader

Guns for training and entertainment

Airsoft gun

BB gun

Paintball gun

Replica gun

Inert gun

Spud gun

Water gun

Nerf gun