Breechblock

Part of speech: noun

Definitions

1. A mechanical part in firearms that seals the rear of the chamber during firing, controls gas escape, and facilitates the removal of fired cartridges
2. This component functions by preventing gas leakage while securing ammunition, allowing safe discharge and extraction in firearms
3. A crucial element in firearms that prevents gas from escaping during firing, holds rounds securely, and assists in the extraction of spent cartridges

Etymology: The breechblock is a compound of two plain English words, and each half carries an older history of its own. "Breech" comes from Old English "brēc", a plural form that once referred to the hinder parts of the body, and it came to mean the rear end of a gun barrel, the end opposite the muzzle where the charge is loaded. "Block" is an older English word for a solid piece of wood or stone, and it was already used for the solid mass that stops or fills something. Put together, the name describes exactly what the part does: it is the solid block closing off the breech. Because the term is built from two transparent parts, its meaning follows directly from them. Its function is to close the rear of the chamber so that the pressure of the burning charge pushes against solid metal instead of escaping backward, and in many designs it can be swung or slid open so that a spent cartridge can be pulled out and a fresh one loaded.