Definition

Noun: A breechblock is the solid, movable metal component in a breech-loading firearm. Its primary function is to close the rear opening (the breech) of the gun's barrel. It is mechanically locked in place before firing to contain the high pressure generated by the propellant.

Usage

The term breechblock is used specifically in the context of firearms engineering and mechanics. It refers to the key part that seals the breech. - The design of the rifle's breechblock is crucial for safety and reliability. - After inserting the cartridge, the soldier slammed the breechblock shut.

Advanced Usage

• Breechblock mechanism: Refers to the entire system involving the block's movement, locking, and unlocking.
  • The falling-block action uses a simple yet strong breechblock mechanism.
• To lock the breechblock: The action of securing the block in the closed position.
  • Ensure the breechblock is fully locked before firing.

Variants and Related Words

• Breech (noun): The rear part of a firearm barrel where the cartridge is loaded.
• Bolt (noun): In many modern rifles, the bolt assembly performs the function of a breechblock. While often used interchangeably in casual discussion, a bolt is typically a type of breechblock that also incorporates the firing pin and extractor.

Synonyms

• Bolt (in specific firearm contexts)
• Breech plug (in some historical or specific designs)

Related Phrases

• Breechblock face: The front surface of the breechblock that supports the base of the cartridge.
  • Inspect the breechblock face for any signs of wear or corrosion.
• Breechblock lug: A projecting part of the breechblock that engages with the receiver to lock it in place.
  • The locking lugs on the breechblock fit into corresponding recesses in the receiver.

Noun

1. a metal block in breech-loading firearms that is withdrawn to insert a cartridge and replaced to close the breech before firing