A firearm is any type of gun that uses an explosive charge and is designed to be readily carried and operated by an individual. The term is legally defined further in different countries.
A submachine gun (SMG) is a magazine-fed automatic carbine designed to fire handgun cartridges. The term "submachine gun" was coined by John T. Thompson, the inventor of the Thompson submachine gun, to describe its design concept as an automatic firearm with notably less firepower than a machine gun. As a machine gun must fire rifle cartridges to be classified as such, submachine guns are not considered machine guns. The submachine gun was developed during World War I (1914–1918) as a close quarter offensive weapon, mainly for trench raiding. At its peak during World War II (1939–1945), millions of submachine guns were made for assault troops and auxiliaries whose doctrines emphasized close-quarter suppressive fire. New submachine gun designs appeared frequently during the Cold War, especially among special forces, covert operation commandos and mechanized infantrymen. Submachine gun usage for frontline combat decreased in the 1980s and 1990s, and by the early 21st century, submachine guns have largely been replaced by assault rifles, which have a longer effective range, have increased stopping power, and can better penetrate the helmets and body armor used by modern soldiers. However, they are still used by security forces, police tactical units, paramilitary and bodyguards for close-quarters combat because they are "a pistol-caliber weapon that's easy to control, and less likely to overpenetrate the target".
A semi-automatic rifle is an auto-loading rifle that fires a single round of ammunition at a time. It uses part of the fired cartridge's energy to eject the case and automatically loads another cartridge into its chamber. This is in contrast to bolt-action or lever-action rifles, which require the user to manually chamber a new round before they can fire again, and fully automatic rifles which fire continuously while the trigger is held down.
In firearms terminology, an action is the functional mechanism of a breechloading firearm that handles the ammunition cartridges, or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all those are single-shot firearms with a closed off breech with the powder and projectile manually loaded from the muzzle. Instead, the muzzleloader ignition mechanism is referred to as the lock.
A semi-automatic pistol is a repeating handgun that automatically ejects and loads cartridges in its chamber after every shot fired, but only one round of ammunition is fired each time the trigger is pulled. The pistol's fire control group disconnects the trigger mechanism from the firing pin/striker until the trigger has been released and reset manually, unlike the self-cycled firing mechanism in fully automatic pistols.
The vz. 58 is a 7.62×39mm assault rifle that was designed and manufactured in Czechoslovakia and accepted into service in the late 1950s as the 7,62 mm samopal vzor 58, replacing the vz. 52 self-loading rifle and the 7.62×25mm Tokarev Sa 24 and Sa 26 submachine guns.
A firearm is said to fire from an open bolt or open breech if, when ready to fire, the bolt and working parts are held to the rear of the receiver, with no round in the chamber. When the trigger is actuated, the bolt travels forward, feeds a cartridge from the magazine or belt into the chamber, and fires that cartridge in the same movement. Like any other self-loading design, the action is cycled by the energy released from the propellant, which sends the bolt back to the rear, compressing the mainspring in readiness for firing the next round. In an open-bolt gun firing semi-automatically, the bolt is caught and held at this point by the sear after each shot; and in automatic open-bolt fire, it's caught and held in this manner whenever the trigger is released. In contrast to this, in closed-bolt guns, the trigger and sear do not affect the movement of the bolt directly.
Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gas created by the ignition of the propellant charge.
A breechblock is the part of the firearm action that closes the breech of a breech loading weapon before or at the moment of firing. It seals the breech and contains the pressure generated by the ignited propellant. Retracting the breechblock allows the chamber to be loaded with a cartridge.
The Škorpion vz. 61 is a Czechoslovak machine pistol developed in 1959 by Miroslav Rybář (1924–1970) and produced under the official designation Samopal vzor 61 by the Česká zbrojovka arms factory in Uherský Brod from 1963 to 1979. The standard version uses .32 ACP ammunition.
Gas-operation is a system of operation used to provide energy to operate locked breech, autoloading firearms. In gas-operation, a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to dispose of the spent case and insert a new cartridge into the chamber. Energy from the gas is harnessed through either a port in the barrel or a trap at the muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and locking of the action.
Rotating bolt is a method of locking the breech of a firearm closed for firing. Johann Nicolaus von Dreyse developed the first rotating bolt firearm, the "Dreyse needle gun", in 1836. The Dreyse locked using the bolt handle rather than lugs on the bolt head like the Mauser M 98 or M16. The first rotating bolt rifle with two lugs on the bolt head was the Lebel Model 1886 rifle. The concept has been implemented on most firearms chambered for high-powered cartridges since the 20th century.
The Mendoza RM2 was a light machine gun manufactured in Mexico by Productos Mendoza, S.A..
The StG 45(M) (abbreviation of Sturmgewehr 45, "Assault Rifle 45") sometimes referred to as the MP 45(M), was a prototype assault rifle developed by Mauser for the Wehrmacht at the end of World War II, using an innovative roller-delayed blowback operating system. It fired the 7.92×33mm Kurz (or "Pistolenpatrone 7.9mm") intermediate cartridge at a cyclic rate of around 450 rounds per minute.
The ČZ 2000 is a prototype 5.56 mm caliber Czech weapon system, consisting of a standard rifle, carbine and light machine gun. The system was developed in 1991 after adapting the LADA firearm prototype J. Denel from the Brno-based Prototypa-ZM company is the chief designer for both systems. The ČZ 2000 was to be produced by Česká zbrojovka of Uherský Brod. It was planned to be the new service weapon of the Czech Army, replacing: the 7.62 mm vz. 58 assault rifle, 7.65 mm vz. 61 Škorpion submachine gun and 7.62 mm vz. 59 machine gun. As of 2007, the project has been discontinued.
The SG 540 is a 5.56×45mm NATO assault rifle developed in the early 1970s by Schweizerische Industrie Gesellschaft of Neuhausen, Switzerland as a private venture primarily destined for export markets and as a potential replacement for the 7.5×55mm Swiss SG 510 automatic rifle known as the Stgw 57 in Swiss service.
The MG 45 was a machine gun based on the MG 42, which was developed but not fielded in significant numbers by the German Army in World War II.
Recoil operation is an operating mechanism used to implement locked-breech autoloading firearms. Recoil operated firearms use the energy of recoil to cycle the action, as opposed to gas operation or blowback operation using the pressure of the propellant gas.
A repeating firearm or repeater is any firearm that is designed for multiple, repeated firings before the gun has to be reloaded with new ammunition.
