All About Pistols – Semi-Automatic Pistols

Pistols come in a wide array of types for various purposes and needs. Here you can learn about pistol sizes, calibers, actions, and styles. Learn the working parts of a pistol, what makes it fire, need-to-know terminology, and more.

There are two main types of handguns:

Semi-Automatic Pistols

A semi-automatic pistol is a type of handgun with a single chamber and barrel. The gun fires a chambered round, extracts and ejects the empty casing and then loads a new round into the room (if additional games are in the magazine) with each trigger pull.


A revolver is a handgun that contains a cylinder with multiple chambers. When the trigger is pulled, the cylinder rotates around a central pin to align the next chamber with the firing pin. A single barrel will fire one round per trigger pull.

How A Semi-Automatic Pistol Works

Eight actions occur as a pistol fires a projectile:

  1. Feeding – Moves a cartridge from the magazine toward the barrel.
  2. Chambering – A cartridge moves fully into the barrel chamber area.
  3. Locking – The barrel and slide ‘lock’ together mechanically.
  4. Firing – The firing pin hits the cartridge primer, the powder is lit, pressure builds, and the projectile (bullet) leaves the barrel.
  5. Unlocking – The slide and barrel mechanically separate slightly.
  6. Extracting – The slide moves rearwards, and the extractor ‘hook’ pulls the empty cartridge casing out of the barrel by its rim.
  7. Ejecting – The ejector hits the empty cartridge rim, turning it/pushing it out the slide ejection port.
  8. Cocking (resetting the action) – The trigger and the firing pin are set together and ready to fire another round.

What is the Action of a Gun?

The action of the gun consists of all the moving parts that facilitate the loading, firing, discharging of the empty case, and unloading of the gun. There are two types of action:

A long trigger pull both cocks and releases the hammer/firing pin to fire the gun.
The trigger is used only to release the hammer/firing pin and does not cock the firing mechanism.

Other Parts Of A Pistol


The trigger guard is the material around the trigger that provides protection and safety.


The hammer impacts the firing pin or cartridge directly, discharging the ammo.

Firing pin

The firing pin is the hardened pin centered behind the primer of a chambered cartridge. When struck by the hammer, it impacts the primer cap of the cartridge and discharges the ammunition.


Ammunition is also known as a ‘cartridge’ or ‘round’. It consists of casing, primer, powder, and projectile.