A Guide to the Basic Parts of a Handgun

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​In preparing a guide to the three basic parts of a handgun, I examined many different handguns. These included single action revolvers, double action revolvers, and several different types of semi automatic pistols. After going over these, I settled just what these key parts are, and how they differ among types of guns.

​Pistols and Handguns

Words like pistol and handgun are commonly interchangeable words. However, old fashioned usage still persists in some areas, and pistol sometimes is used to refer to what is most commonly known as a semi automatic handgun.

Although the ​use of the handguns are practically the same, this sometimes confusing usage is rooted in nuances of language that are mostly obsolete.

For this article, I will treat “pistol” and “handgun” as the same. When the distinction of a semi automatic pistol must be made, it will be described as such. Similarly, unless otherwise needed, all types of revolvers will be lumped into the single word “revolver”.

Semi automatic pistol held at shooting point within a grassy land

​Types of Handguns

There are 3 basic types of handguns:

  • Single shot pistols- now used almost exclusively for hunting and target shooting
  • Revolvers- which use a rotating cylinder to hold ammo
  • Semi automatic pistols- use gas or recoil energy to cycle a round

Because single shots are uncommon, I will not look at them in this article. However, if you are looking for gear such as a good-range backpack, then check out my full buying guide here.

Revolvers can be single action or double action. A single action must have the hammer cocked for each round. A double action means the trigger can be squeezed for each round fired without having to manually cock the hammer. Single action revolvers today are used for hunting and target shooting.

Semi automatic pistols can also be single or double action. In this case, the initial act of chambering a round cocks the hammer the first time, and then the cycling of the gun cocks it for each round fired. However, three basic parts of a handgun remain nearly the same for most semi auto handguns.

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​Unusual and Uncommon Handguns

​It is not the purpose of this article to touch on handguns that fall outside the most common guns. There are many handguns built on rifle actions. While fun to own and shoot, these kinds of guns are a special case, and each one may have basic part types that do not apply to others rifle based handguns.

​The Three Main Parts

​Broadly speaking, the three main parts of a handgun:

  • barrel
  • frame or receiver
  • either the slide or the cylinder

For single shot pistols this will be the frame, barrel and stock or grip. I am going to start looking at these three types of guns and examining the parts.

Black handgun laid flat on a marble countertop

​Single Shot Pistols

​Every gun has a frame. On a single shot pistol, the frame will be what the barrel attaches to, and will also contain the trigger group, and depending on the model, you may have a rear sight as well. The frame (also known as receiver or action) is the heart of any gun.

Attached to the frame is a barrel. The barrel may be a break open action which allows loading a round directly into the barrel, or it will be attached to the receiver if the gun is a bolt action.

Barrels usually also have fixed sights or the means to attach a scope or optic. The latest technology called​ smart guns work the same way, except that it takes a few more steps before a shooter gets to fire the gun.

A single shot pistol also must have a grip for holding the gun. Because of the simple nature of the gun, this last major component is also critical. A well designed grip enhances accuracy and attaches directly to the receiver at the back of the pistol.


​Revolvers use a rotating cylinder which is advanced by a hammer being cocked manually or by a trigger pull. The first of the three basic parts of a handgun that apply to a revolver is this cylinder. The cylinder holds the ammo, and rotates to bring a live round under the hammer.

The next part is the frame. As with any gun, the frame or receiver is where the barrel attaches, and any other parts needed for fire are installed. On a revolver I’ll find the trigger and hammer assembly here, along with the cylinder and grips, making it the heart of the entire gun.

The last of the three major components of a pistol is the barrel. Pinned or screwed into the frame, the barrel also has the forcing cone which guides the bullet into the bore and ensures the round is perfectly centered. Barrels can be very short, or very long, and will be fitted with sights.

​Semi Automatic Pistols

​When asking what are the three main parts of a handgun, you are probably seeing some common themes repeated. As with all pistols, the frame is a main part of a semi automatic pistol. Along with the trigger and other fire control parts, it also holds the magazine, slide, and barrel.

In common with other types of handguns, the barrel is a major part of a semi-automatic pistol. The barrel may be pinned or screwed to the frame, or attached with link with a removable pin through the frame, although there are less common methods that are also used.

The slide is the last major pistol part to consider here. The slide can take many different forms, but always rides around the barrel and cycles with a fired round to eject a spent round and load a fresh one from the magazine. Front and rear sights are also mounted to the slide.

​Other Common Parts

I’ve seen the 3 parts can vary a bit depending on the type of pistol. Two parts – the barrel and frame are universal to all guns, and in fact must always be present. While slides and cylinders belong to unique classes of pistols.

Empty, silver revolver laid flat on soil with a few scattered bullets and a footprint

All guns of course have a trigger which is used to actually fire the gun. The trigger is pressed and releases the hammer if a gun is fitted with one. Striker fired guns like the Glock will have their striker released instead, the end result is the same, with the gun firing.

Many guns have hammers- either built inside the gun or outside of the gun. External hammers can be manually cocked back, while internal hammers must be cocked through slide action or the pull of a double action trigger. When the hammer drops, the force of the blow against the firing pin fires a round. This is similar to how a trigger gun lock would work  when it comes to safety measures. There are also other types of locks that work for storage units such as the gun cases in my good firearm cases reviews.

​Other Parts

​Semi-automatic pistols will almost always have a removable magazine which holds ammo. These magazines vary in size and shape, and can hold five or six rounds, or over a hundred! Magazines can wear out, so it is common to own multiple magazines– as for the gun’s body, it is best to keep them clean to make sure they work well.

You might also encounter muzzle brakes on pistols designed for accurate and safe shooting or that fire high-powered rounds. Some pistols will be equipped with a safety, while others by virtue of their design require such deliberate action to fire as to not need a safety. There are a lot of different parts across many different gun designs.


​As you can see, the three main parts of a handgun vary somewhat from type, but there is considerable consistency. You always have a frame and a barrel. Semi automatic pistols have slides. Revolvers have cylinders. These key parts are the heart and soul of a pistol, and without them, they simply don’t work!

James Forrester is a lifelong gun and firearms owner, and an even bigger advocate for gun safety. He created KeepGunsSafe.com with the purpose of sharing helpful tips and educating others on how to keep guns and weapons safe and secure.