The Semi-Automatic like the revolver consists of three components: The frame, the barrel, and the action.
- Grip Panels
- Trigger Guard
- Rear sight
- Safety - a mechanical device designed to reduce the chance of an accidental discharge. Because a safety is a mechanical device that can fail, the precention of an accident is always the responsibility of the gun handler.
- Slide stop - locks the slide in an open position.
- Barrel - as with the revolver, the barrel in a semi-automatic is a metal tube through which the bullet passes.
- Bore - the inside of the barrel.
- Rifling - spiral lands and grooves cut into the bore. The rifling imparts a spin on the bullet that stabilizes it in flight.
- Muzzle - font end of the barrel.
- Caliber - distance between the lands. Measured in decimal fractions of an inch or in millimeters.
- Front sight - used with the rear sight in aiming.
- Slide - On some models, the slide fits around the barrel; on others, it is located at the rear of the barrel. When the pistol is fired, the slide moves to the rear; it is returned to a closed position due to pressure from a slide spring.
- Magazine - a storage device designed to hold cartridges ready for insertion into the chamber.
- Magazine release button - a device that releases the magazine so it can be removed from the pistol.