See Gun Terminology for explanations of some of the terms used on this page.
A handgun with a chamber that is integral with the barrel. The most common types of pistols are the single shot, multi-barreled, semi-automatic and machine. Semi-automatic pistols only take seconds to reload, unlike multi-barreled pistols, where each barrel needs to be reloaded separately. Machine pistols are fully-automatic pistols.
A handgun-style, often magazine-fed and self-loading firearm. It is capable of fully-automatic or burst-fire and is generally chambered for pistol cartridges. They resemble submachine guns, but are more compact to be concealable and can be operated one-handed. Since they are concealable and have a high rate of fire, they are often used by bodyguards from government or private agencies.
A firearm that has a cylinder containing multiple chambers and at least one barrel for firing. The revolving cylinder typically chambers five or six rounds, but some models hold ten rounds or more. Most revolvers are handguns, but other weapons like grenade launchers, shotguns and some rifles also contain a revolving chamber. Revolvers have mostly been replaced by semi-automatic pistols in military and law enforcement applications.
An automatic carbine. It has the automatic fire of a machine gun and the cartridge of a pistol. In the military, the submachine gun has mostly been replaced by carbine-length assault rifles, since they have more power and range. They are still widely used in police and counter-terrorist forces, who typically face opponents in the tight confines of civilian houses.
A fully automatic, mounted or portable firearm, usually designed to fire bullets in quick succession from an ammunition belt or magazine, typically at a rate of several hundred rounds per minute. Machine guns are often mounted, but light machine guns can be held like a rifle. In United States gun law, "machine gun" is a technical term for any fully automatic firearm, and also for any component or part that will modify an existing firearm such that it functions as a fully automatic firearm.
A firearm that is usually designed to be fired from the shoulder. It's generally a smoothbore firearm, which means that the barrel is not rifled. It is capable of discharging more than one projectile down the barrel with a single pull of the trigger. Shotguns are typically used against small and/or fast moving targets and are mostly used as civilian weapons for target shooting sports or bird hunting. They are also used as close quarters combat weapons.
A firearm that is designed to be fired of the shoulder. It has a rifled barrel. Typically a bullet is propelled. Riffles that propel compressed air are called "air rifles" and are popular for vermin control, target shooting or hunting small game. Old rifles fired a single projectile with each squeeze of the trigger, modern rifles are capable of firing more than one round per trigger squeeze. Some fire in fully automatic mode, others are burst-fire. Rifles are used in warfare, hunting and shooting sports.
A selective fire rifle that lets you choose between fully-automatic, semi-automatic and burst-fire. The presence of selective fire modes permits more efficient use of rounds to be fired for specific needs. They are shorter, more accurate and weigh less than a standard rifle. The lower power means that you can fire more bullets faster. These shorter rifles were developed when combat experience had shown that most fights took place at 220-330 yards distance. Assault rifles are the standard service rifles in most modern armies.
A short rifle with a barrel under 16 inches in length. Many carbines are shortened versions of full rifles, firing at a lower velocity due to the shorter barrel length. The shorter barrel makes carbines less accurate for long range shooting, but more effective in close-range combat. Since a single shot has low wounding power, they depend on high volumes of fire for effectiveness. They are used as personal defense weapons and in the military.
Pistol by Augustas Didzgalvis: Creative Commons License.
Revolver by Nemo5576: Creative Commons License.
by Commander Zulu: Creative Commons License.
Rifle by Fantagu: public domain.
Carbine by Sanandros: Creative Commons License.
Assault Rifle: public domain.
Machine Pistol by adamsguns.com: Creative Commons License. Image
Submachine Gun by Cyrillic: Creative Commons License.
Machine Gun: public domain.