The action of a firearm is made up of parts that load, unload, fire, and eject the shotshell or cartridge. Firearms can be classified by their action type — bolt action, lever action, pump action, semi-automatic (or autoloading) action, break (or hinge) action, or revolving action (single action or double action).
A safety is a device that blocks the action to prevent the firearm from shooting until the safety is released or pushed to the off position. The safety is intended to prevent the firearm from being fired accidentally. However, safeties are mechanical devices subject to mechanical failure from wear and other factors.
Repeating firearms have a magazine that stores the ammunition that has not been fired. When you work the action, a cartridge is picked up from the magazine and placed in the chamber ready to be fired. Magazines may be detachable or fixed.
A sight is a device that you use to line up the muzzle with your eye so that you can hit the target. Shotguns usually have a simple pointing bead. The types of sights found on rifles are open, aperture or peep, telescopic or scope (most accurate), and dot. Most handguns have an open sight.