With a semi-automatic action, pulling back the handle of a bolt exposes the chamber to load one round. It is ready to fire after releasing the bolt to close the chamber. Multiple rounds are loaded in a magazine—a tubular magazine is common in rifles and shotguns, and detachable magazines are commonly used in handguns. Each squeeze on the trigger will fire one round, eject the empty case, and load another round automatically (where they get a common name of auto-loader). The trigger must be released before another round can be fired.
Note: A semi-automatic firearm is different from a fully-automatic firearm, which fires continuously as long as the trigger is held down. Fully-automatic firearms are not allowed for hunting or sport shooting.