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ARMAG

Search matches names, aliases and the text of every page. An arm found by its service designation is found by its alias, not its title.

Closed bolt

A firing cycle in which the bolt is already forward and locked between shots; only the hammer or striker moves when the trigger is pulled.

The normal arrangement for a rifle or a pistol, and the less common one for a submachine gun. The round is chambered and the breech shut; pulling the trigger releases only a hammer or a striker. Almost nothing moves, so almost nothing disturbs the aim.

The price is heat. A closed chamber holds a cartridge against a hot barrel, and in a weapon firing long automatic bursts that risks the round igniting on its own. Designs that fire automatically from a closed bolt accept that risk because their rates and their duty cycles are lower than a machine gun’s.