It can refer to two different things. It can refer to the interal parts (springs, levers, etc) that make the gun function, or it can refer to the way the gun operates. A gun that must be cocked before it can be fired is referred to as a single action, for instance.
Design of the firearm
A firearm action refers to the mechanism that loads, fires, and ejects cartridges in a firearm. It encompasses various systems, such as bolt-action, lever-action, pump-action, and semi-automatic, each defining how the firearm operates. This action is crucial for the firearm's functionality and determines its firing sequence and handling characteristics.
Two basic styles of firearm actions are single action and double action.
Half barrel is not a type of firearm action.
Type of firearm action
The action spring is typically housed within the stock or buffer tube of a firearm. It provides the necessary tension to cycle the firearm's action and chamber a new round.
To load a firearm, first ensure the gun is pointed in a safe direction and that your finger is off the trigger. Open the action and insert the ammunition into the magazine or chamber as appropriate for the firearm type. Once loaded, close the action and visually check that the firearm is ready to fire. To unload, point the firearm in a safe direction, open the action, remove the magazine if applicable, and then clear any remaining rounds from the chamber. Always verify that the firearm is empty before handling or storing it.
The action on a firearm refers to the mechanism that loads, fires, and ejects cartridges. It encompasses all the moving parts involved in these processes, such as the bolt, slide, or lever, depending on the type of firearm. The receiver is the core component that houses the action and other critical parts, such as the trigger and magazine, and serves as the main structure to which other components are attached. Essentially, the action and receiver work together to ensure the firearm functions safely and effectively.
No such thing. The Glock is not a double action firearm.
Action or reciever
Stock , Barrel & Action
Not sure if this is what you're asking, but strictly speaking, the action of a firearm refers to how the trigger system works. Some firearms are single action, some are double action, some are double action only, some are variants. Glocks are called "Safe Action" which is Glocks propietary term for how their trigger works.