Glossary
Terms used throughout this database. If a term in a procedure is unfamiliar, it should be here — if it is not, that is a gap worth reporting.
- Action
- The mechanism that loads, fires, and unloads the firearm — bolt, lever, pump, semi-automatic, and so on.
- Bolt carrier group (BCG)
- In AR-pattern rifles, the assembly of bolt, bolt carrier, firing pin, cam pin, and retaining pin that cycles the action.
- Chamber
- The portion of the barrel that holds the cartridge at the moment of firing. Checking it is the last and most important step of verifying a firearm is unloaded.
- Charging handle
- The part used to manually retract the bolt or slide to chamber a round or clear the action.
- Cycle the action
- To work the action through a full open-and-close sequence, as when chambering or ejecting.
- Decocker
- A control that lowers a cocked hammer safely without pressing the trigger.
- Detail strip
- Disassembly beyond field stripping, down to individual components. Usually requires tools and is where most damage happens.
- Drift punch
- A punch used to drive out pins. Using a punch of the wrong diameter or a hardened punch on a soft pin is a common way to mar a firearm.
- Ejector
- The fixed or sprung part that kicks the extracted case clear of the firearm.
- Extractor
- The claw that pulls the spent case out of the chamber. A frequent wear part and a frequent cause of failures to extract.
- Field strip
- The routine disassembly the manufacturer intends the owner to perform for cleaning — typically no tools, or one simple tool.
- Firing pin / striker
- The part that strikes the primer. A striker is a spring-loaded firing pin that is itself the source of energy.
- Function check
- A structured test, performed on a verified-unloaded firearm, that confirms the safety, trigger, reset, and action work correctly after reassembly.
- Gas block / gas system
- The components that tap expanding gas from the barrel to cycle a gas-operated action.
- Headspace
- The distance from the breech face to the point in the chamber that stops forward cartridge motion. Incorrect headspace is dangerous and is gunsmith territory.
- In battery
- The state where the action is fully closed and locked, ready to fire. A firearm out of battery should never be fired.
- Loading gate
- The hinged cover on the side of a single-action revolver or tube-magazine rifle through which cartridges are loaded.
- Magazine release
- The control that frees the magazine from the firearm. Not to be confused with the magazine itself, which is not a 'clip'.
- Manual of arms
- The standard set of handling procedures for a given firearm — how you load, unload, clear, and make it safe.
- Muzzle
- The front end of the barrel, where the projectile exits. Muzzle direction is the first safety consideration in every procedure.
- Recoil spring assembly
- The spring (often captive on a guide rod) that returns the slide or bolt to battery. Frequently under tension during disassembly.
- Safe direction
- A direction in which an unintended discharge would not cause injury or unacceptable damage. It is a judgment you make about your specific location.
- Sear
- The part that holds the hammer or striker cocked until the trigger releases it. Sear work is gunsmith territory — mistakes here cause unintended discharges.
- Slide stop / slide release
- On most semi-automatic pistols, the lever that holds the slide open on an empty magazine and, on many designs, doubles as the takedown part.
- Takedown pin / lever
- The pin or lever that, when moved, allows the major assemblies to separate.
- Trigger reset
- The point during trigger release at which the mechanism re-engages and the firearm can fire again. Checking it is part of a function check.
- Tube magazine
- A magazine built as a tube, usually under the barrel or in the stock. Unloading one requires cycling rounds out or using a dedicated unloading procedure.