Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Components (hierarchy name)
4. components (objects parts)
5. [components by specific context]
6. weapon components
7. projectile weapon components
8. firearm components
9. [breech mechanisms and breech mechanism components]
10. breech mechanism components
11. breechblocks

Anotations

Scope note:

Sliding breechblocks incorporating a firing pin, cartridge case extractor, and one or more lugs to lock them into firing position, found in bolt action, automatic, and semiautomatic breechloading rifles, machine guns, and submachine guns with blowback action. They guide ammunition into the chamber and rotate to lock the breech mechanism.