What is the portion of the firearm that loads, fires and ejects a cartridge or shot shell called?

The part of the firearm that loads, fires, and ejects a cartridge or shotshell is known as the action. This is a crucial component because it encompasses all of the mechanisms that enable the firearm to operate effectively. The action is responsible for several key functions: it is where the ammunition is chambered, it initiates the firing sequence, and it manages the ejection of spent cartridges once they have been fired.

Understanding the function of the action helps to grasp how firearms operate on a basic mechanical level. For example, different types of firearms have varying designs of actions, such as semi-automatic, bolt action, or pump action, each with unique characteristics pertaining to how they load and fire. Recognizing the action as the central part of the firearm's functionality is essential for safe handling and operation.

In contrast, the stock is the part of the firearm that is held against the shoulder, the trigger is the mechanism that initiates the firing process, and the barrel is the tube through which the bullet or shot travels after being fired. Each of these parts has specific purposes, but it is the action that fundamentally governs the loading, firing, and ejection functions of the firearm.