What type of action does a semi-automatic firearm use?

A semi-automatic firearm utilizes a self-loading action, which means that each time the firearm is discharged, it automatically extracts and ejects the spent cartridge casing and chambers a new round from the magazine without needing the shooter to manually operate the action. This self-loading mechanism allows for a quicker follow-up shot compared to other types of actions like single-shot or break action firearms, which require manual loading for each shot.

The self-loading process is significant because it provides a user-friendly experience, allowing shooters to maintain focus and stability when aiming, as they do not need to take their hands off the firearm to reload after each shot. This functionality is inherent to how semi-automatic firearms are designed, distinguishing them from other action types that rely on more manual operations or specific mechanisms.