Barrel box , bolt box - a part or set of parts designed to lock the barrel and place the main mechanisms of small arms (locking, trigger, shock and safety), as well as the bolt engagement with the barrel. In self-loading weapons, it also includes a cartridge receiver.
In addition to securing the connection of parts and mechanisms of the weapon, the receiver serves to place the bolt group (bolt or bolt) and set the nature of its movement, ensure the operation of the mechanism for feeding cartridges into the barrel, closing the barrel bore with a shutter and locking the shutter. In the middle, as a rule, the trigger mechanism is placed. She herself protects the mechanism of weapons from pollution and breakdowns.
In a professional environment, it is customary to distinguish between receiver and bolt boxes by the presence of combat stops in them. In systems such as a Kalashnikov assault rifle (modernized), a Mosin rifle, a Mauser 98 rifle, there is a receiver where the barrel is screwed in or pressed in (pinned), and the supports for the combat stops are placed in the box. In systems such as the M16 rifle, Blazer R8 and P93 carbines, there is a bolt box, where a quick-detachable barrel is fastened with stops made integrally with the barrel itself or in the form of a sleeve.