A semi-automatic rifle is an autoloading rifle that fires a single cartridge with each pull of the trigger. 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 rifles, which require the user to cycle the bolt manually before they can fire a second time, and fully automatic rifles which fire continuously until the trigger is released.
In firearms terminology, an action is the functional mechanism of a breech-loading 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 bullpup firearm is one with its firing grip located in front of the breech of the weapon, instead of behind it. This creates a weapon with a shorter overall length for a given barrel length, and one that is often lighter, more compact, concealable and more maneuverable than a conventionally configured firearm. Where it is desirable for troops to be issued a more compact weapon, the use of a bullpup configuration allows for barrel length to be retained, thus preserving muzzle velocity, range and ballistic effectiveness.
An automatic rifle is a type of autoloading rifle that is capable of fully automatic fire. Automatic rifles are generally select-fire weapons capable of firing in semi-automatic and automatic firing modes. Automatic rifles are distinguished from semi-automatic rifles in their ability to fire more than one shot in succession once the trigger is pulled. Most automatic rifles are further subcategorized as battle rifles or assault rifles.
The SKS is a semi-automatic rifle designed by Soviet small arms designer Sergei Gavrilovich Simonov in 1945.
The ArmaLite AR-18 is a gas-operated assault rifle chambered for 5.56×45mm NATO ammunition. The AR-18 was designed at ArmaLite in California by Arthur Miller, Eugene Stoner, George Sullivan, and Charles Dorchester in 1963 as an alternative to the Colt AR-15 design, a variant of which had just been selected by the U.S. military as the M16. A semi-automatic version known as the AR-180 was later produced for the civilian market. While the AR-18 was never adopted as the standard service rifle of any nation, its production license was sold to companies in Japan and the United Kingdom, and it is said to have influenced many later weapons such as the British SA80, the Singaporean SAR-80 and SR-88, the Belgian FN F2000, the Japanese Howa Type 89 and the German Heckler and Koch G36.
The Type 63 is a Chinese-designed assault rifle with a resemblance to the SKS. The weapon features a fully-automatic rotating bolt system modified from the Type 56 assault rifle instead of the tilting bolt system of the SKS. Overall, the weapon is based on the Type 56 carbine and the Type 56 assault rifle which are both used by the People's Liberation Army. Due to its inadequate performance and accuracy, further compromised by poor quality control due to the Cultural Revolution, the Type 63 was in service with the People's Liberation Army for only about 15 years.
The MAS-49 is a French semi-automatic rifle that replaced various bolt-action rifles as the French service rifle that was produced from 1949. It was designed and manufactured by the government-owned MAS arms factory. The French Army formal designation of the MAS-49 is Fusil semi-automatique 7 mm 5 M. 49.
The FN F2000 is a 5.56×45mm NATO bullpup rifle, designed by FN Herstal in Belgium. Its compact bullpup design includes a telescopic sight, a non-adjustable fixed notch and front blade secondary sight. The weapon has fully ambidextrous controls, allowed by a unique ejection system, ejecting spent cartridge casings forward and to the right side of the weapon, through a tube running above the barrel. The F2000 made its debut in March 2001 at the IDEX defence exhibition held in Abu Dhabi, in the United Arab Emirates.
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.
The Cei-Rigotti is an early automatic rifle created in the final years of the 19th century by Amerigo Cei-Rigotti, an officer in the Royal Italian Army. Although the rifle was never officially adopted by any military, it was tested extensively by the Italian Army during the lead-up to the First World War.
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 Karabin samopowtarzalny wzór 38M, was a prototype Polish 7.92mm semi-automatic rifle used by the Polish Army during the Invasion of Poland of 1939.
Ferdinand Ritter von Mannlicher was an Austrian engineer and small arms designer. Along with James Paris Lee, Mannlicher was particularly noted for inventing the en-bloc clip charger-loading box magazine system. Later, while making improvements to other inventors' prototype designs for rotary-feed magazines, Mannlicher, together with his protégé Otto Schönauer, patented a perfected rotary magazine design, the Mannlicher–Schönauer rifle, which was a commercial and military success.
The M1941 Johnson Rifle is an American short-recoil operated semi-automatic rifle designed by Melvin Johnson prior to World War II. The M1941 unsuccessfully competed with the contemporary M1 Garand rifle but was used in limited numbers by the US Marines during the Second World War.
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 FN FNC is a 5.56×45mm NATO assault rifle developed by the Belgian arms manufacturer FN Herstal and introduced in the late 1970s.
Tilting bolt action is a type of locking mechanism often used in self-loading firearms and, rarely, in straight-pull repeating rifles. Essentially, the design consists of a moving bolt driven by some mechanism, most often a piston with gas pressure from the gas port behind the muzzle. The bolt drops down into receiver recess and locks on bolt closing. Tilting the bolt up and down locks-unlocks in the breech. This tilting allows gas pressure in the barrel from firing the gun to lower to safe levels before the cartridge case is ejected.
