Selective fire

Selective fire

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A selective fire firearm
Firearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...

 has at least one semi–automatic
Semi-automatic firearm
A semi-automatic, or self-loading firearm is a weapon which performs all steps necessary to prepare the weapon to fire again after firing—assuming cartridges remain in the weapon's feed device or magazine...

 and one automatic
Automatic firearm
An automatic firearm is a firearm that loads another round mechanically after the first round has been fired.The term can be used to refer to semi-automatic firearms, which fire one shot per single pull of the trigger , or fully automatic firearms, which will continue to load and fire ammunition...

 mode, which is activated by means of a selector which varies depending on the weapon's design. Some selective fire weapons utilize burst fire
Burst mode (firearm)
In automatic firearms, burst mode or burst fire is a firing mode enabling the shooter to fire a predetermined number of rounds, usually 2 or 3 rounds and 100+ on anti-aircraft weapons, with a single pull of the trigger. This firing mode is commonly used in submachine guns, assault rifles and carbines...

 mechanisms to limit the maximum or total number of shots fired automatically in this mode. The most common limits are two or three rounds per pull of the trigger.

Design


Selective fire weapons, by definition, have a semi-automatic mode, where the weapon automatically reloads the chamber
Chamber (weaponry)
In firearms, the chamber is that portion of the barrel or firing cylinder in which the cartridge is inserted prior to being fired. Rifles and pistols generally have a single chamber in their barrels, while revolvers have multiple chambers in their cylinders and no chamber in their barrel...

 after each fired round, but requires the trigger be released and pulled again before firing the next round. This allows for rapid and (in theory) aimed fire. In some weapons, the selection is between different rates of automatic fire and/or varying burst limiters. The selection is often by a small rotating switch often integral with the safety catch or a switch separate from the safety, as in the British SA80
SA80
The SA80 is a British family of 5.56mm small arms. It is a selective fire, gas-operated assault rifle. SA80 prototypes were trialled in 1976 and production was completed in 1994....

 family. Another method is a weighted trigger, such as the Steyr AUG
Steyr AUG
The AUG is an Austrian bullpup 5.56mm assault rifle, designed in the early 1970s by Steyr Mannlicher GmbH & Co KG . The AUG was adopted by the Austrian Army as the StG 77 in 1977, where it replaced the 7.62mm StG 58 automatic rifle...

, which will fire a single shot when 8.8 – 15.4 pounds of weight is exerted on the trigger, and then become fully automatic when over 15.4 pounds of weight is applied. This is useful for emergency situations where a rapid volley of rounds is more effective for suppressing a close enemy rather than a single round burst.

Some selective fire weapons offer a burst mode as the second option, where each pull of the trigger automatically fires a predetermined number of rounds (generally two or three), but won't fire any more until the trigger is pulled again. The current U.S. standard assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...

, the M16A4, and the M4 carbine
M4 carbine
The M4 carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16, all based on the original AR-15 designed by Eugene Stoner and made by ArmaLite. It is a shorter and lighter variant of the M16A2 assault rifle, with 80% parts commonality.It is a gas-operated,...

 variant of this rifle fire a maximum of three rounds with each pull of the trigger in burst mode
Burst mode (firearm)
In automatic firearms, burst mode or burst fire is a firing mode enabling the shooter to fire a predetermined number of rounds, usually 2 or 3 rounds and 100+ on anti-aircraft weapons, with a single pull of the trigger. This firing mode is commonly used in submachine guns, assault rifles and carbines...

. In this design, it retains the count of previously fired rounds and may fire fewer than three rounds. Other designs reset the count with each trigger pull allowing a uniform three round burst as long as rounds remain.

A common version of the Heckler & Koch MP5
Heckler & Koch MP5
The Heckler & Koch MP5 is a 9mm submachine gun of German design, developed in the 1960s by a team of engineers from the German small arms manufacturer Heckler & Koch GmbH of Oberndorf am Neckar....

 submachine gun
Submachine gun
A submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...

 (widely used by SWAT
SWAT
A SWAT team is an elite tactical unit in various national law enforcement departments. They are trained to perform high-risk operations that fall outside of the abilities of regular officers...

 teams and military
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...

 special operations personnel) fires single shots, three-round-bursts, and fully automatically. A special variant uses a two-round-burst to minimize the chances of missing with a third round. Some automatic cannons have larger burst limiters to coincide with higher rates of fire.

Selective fire weapons are regulated in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 under the National Firearms Act
National Firearms Act
The National Firearms Act , 73rd Congress, Sess. 2, ch. 757, , enacted on June 26, 1934, currently codified as amended as , is an Act of Congress that, in general, imposes a statutory excise tax on the manufacture and transfer of certain firearms and mandates the registration of those firearms. The...

 of 1934; their new manufacture for the civilian market was prohibited by the Firearm Owners Protection Act
Firearm Owners Protection Act
The Firearm Owners' Protection Act , , codified at et seq., is a United States federal law that revised many statutes in the Gun Control Act of 1968.-Federal Firearms License regulatory reform:...

 of 1986. Those still in circulation often command prices significantly higher than similar models still available to law enforcement and military agencies.

See also

  • List of firearms
  • Bump fire
    Bump fire
    Bump firing is the act of using the recoil of a firearm to fire multiple shots in rapid succession. This process involves holding the foregrip with the non-trigger hand, releasing the grip on the firing hand , pushing the rifle forward in order to apply pressure on the trigger finger from the...

    - a technique to simulate fully automatic firing with a semi-automatic rifle