Editing Machine gun (section)

== Operation ==
[[File:DIRECTM16.gif|thumb|Direct impingement]]
[[File:PISTONM16.gif|thumb|Gas piston]]

Many machine guns are of the [[locked breech]] type, and follow this cycle:

* Pulling (manually or electrically) the bolt assembly/bolt carrier rearward by way of the cocking lever to the point bolt carrier engages a [[sear (firearm)|sear]] and stays at rear position until trigger is activated making bolt carrier move forward
* Loading fresh round into chamber and locking bolt
* Firing round by way of a firing pin or striker (except for aircraft medium calibre using electric ignition primers) hitting the primer that ignites the powder when bolt reaches locked position.
* Unlocking and removing the spent case from the chamber and ejecting it out of the weapon as bolt is moving rearward
* Loading the next round into the firing chamber. Usually, the recoil [[Spring (device)|spring]] (also known as main spring) tension pushes bolt back into battery and a [[Cam (mechanism)|cam]] strips the new round from a feeding device, belt or box.
*Cycle is repeated as long as the trigger is activated by operator. Releasing the trigger resets the trigger mechanism by engaging a [[sear (firearm)|sear]] so the weapon stops firing with bolt carrier fully at the rear.

The operation is basically the same for all locked breech automatic firearms, regardless of the means of activating these mechanisms.  There are also multi-chambered formats, such as [[revolver cannon]], and some types, such as the [[Schwarzlose machine gun]] etc., that do not lock the breech but instead use some type of delayed [[blowback (firearms)|blowback]].