The two basic styles of firearm actions are single-shot and repeating.
Single-shot actions
A single-shot firearm holds only one round in the chamber and must be manually reloaded after each shot. These designs are common in some rifles, shotguns, and pistols used for training, target shooting, and certain types of hunting where simplicity is valued.
Repeating actions
A repeating firearm has a magazine, cylinder, or multiple barrels that store additional cartridges or shotshells so multiple shots can be fired before reloading the gun completely. Common repeating mechanisms include bolt-action, lever-action, pump-action, and semi-automatic systems, which all allow faster follow-up shots than single-shot firearms.