The Parts of a Semi-Automatic
The next four pictures show the parts of a semi-automatic handgun.
The frame is the body of the gun. Everything else attaches to it.
The slide is shown in its forward position above. The slide moves rapidly back and forward on the frame each time the gun is fired. It is shown in forward position above and the back position in the picture below. When the slide moves in this back and forth manner, it ejects a discharged cartridge through the ejection port, seats a new cartridge by stripping the top cartridge off the magazine and placing it in the chamber ready to shoot, and prepares the gun for the next shot.
The grip is what you hold onto when you are shooting.
The trigger guard protects the trigger from being depressed accidentally.
The magazine holds the ammunition. It can be taken out of the gun to be loaded with ammunition. After you load it with ammunition, you place it back into the gun.
The front sight and rear sight help you aim the gun.
This picture shows the same pistol with the slide in the locked-back or open position. This position exposes the barrel of the gun (which is inside the slide) and opens the ejection port.
You can place the slide into the locked-back position by pulling the slide back manually and moving the slide-lock lever up. This locks the slide into the open position.
The front end of the barrel is called the muzzle. The muzzle is where the bullet comes out after you pull the trigger.
The next picture shows the back end of the barrel, which is called the breech. In a semi-automatic, the back end of the barrel is also called the chamber because that is where the bullet sits at the moment it is discharged.
In the picture above, you are looking at the breech through the open ejection port of the gun.
This final picture shows the various moving parts of a semi-automatic that you manipulate to operate the gun. This gun has a full set of buttons and levers to operate. Many semi-automatics are sold without one or more of these buttons or levers.
The trigger fires the gun if a round is in the chamber, the hammer is cocked, and the safety is off. Not all semi-automatics have a safety.
The magazine release is a button on this gun. When you push it in, the magazine will drop out of the gun.
The slide lock is used to lock the slide in the open position. Not all semi-automatics have a slide lock.
The hammer is shown locked-back in the cocked position. Not all semi-automatics have a hammer.
The safety is in the “off” position. That means it is not preventing the gun from firing. You can see it is in the off position because you can see a colored dot below the safety. When you can see color, the safety is off and you should be able to shoot the gun.
The take-down lever unlocks the slide from the frame and allows you to take the gun apart for cleaning and maintenance. Although this configuration is not unusual, there are many different mechanisms to unlock the slide and frame. So you won’t necessarily see a take-down lever on your gun.
How a Semi-Automatic Works
The following videos show animated representations of how a semi-automatic pistol operates.
How a single-action semi-automatic works:
How a Glock (double-action only) works: