Learning the Parts of a Gun: A Guide to Terminology & Functionality

“With great power comes great responsibility” may have been the proverb Uncle Ben said to Peter Parker in Sam Raimi’s cinematic classic, but this same adage can also be applied to firearm owners of all experience levels, especially first-time users.

Understanding the basic parts of a gun inside and out isn’t just a necessity to pass your concealed carry permit, but also a preventative measure to avoid any potentially harmful accidents.

Guns have come a long way from their 10th-century roots in China. They are no longer spear-firing mechanisms made out of bamboo tubes and gunpowder. Modern firearms are assembled out of steel, plastic, aluminum, or a combination of these high-strength materials. 

Basic Parts of a Gun

Let’s start by taking a closer look at the main parts of a handgun, rifle, and shotgun. Firearms are made up of hundreds of individual components, but consist of a few main parts: the frame, the stock, the clip or cylinder, the action, and the barrel.

Action: The mechanism that loads, fires, locks, and ejects the ammunition. The action-type depends on the firearm type.

1. Single-shot handguns are reloaded with every shot. 
2. Repeating handgun revolvers and semi-automatic pistols feature multiple cartridges.
3. Break/hinge action handguns can be found on single-shot handguns or revolver pistols and are popular for first-time firearm owners. A release drops the barrel downward for easy ejection and loading of cartridges.
4. Semi-automatic (unloading action) handguns eject cartridge cases and reload the chamber automatically.
5. Revolving action handguns involve a revolving chamber (either single or double action) containing a number of cartridge chambers.

Barrel: A long metal tube that extends from the frame and directs the bullet upon shooting the firearm. Barrel length varies by firearm type.

1. Muzzle: The front end of the barrel
2. Bore: The interior of the barrel. Spiraling grooves cut into the rifled bore add a spiral spin on bullets when fired. A firearm’s caliber refers to the diameter of the bore.
3. Breech: The rear end of the barrel where you insert the cartridge.

Stock: The butt/handle/grip of a firearm.

Frame/Receiver: The steel housing that connects to every part of the firearm.

Clips/Cylinders: Clips store several rounds of ammunition in a single unit. A cylinder is part of a revolver and contains multiple chambers, each holding a single cartridge.

Gun Anatomy: Internal and External Components

Firearms feature a number of internal and external components that power the firing system.

Trigger: The mechanism that causes the firing of the firearm.

Trigger Guard: A loop around the trigger used to prevent accidental discharge.

Hammer: The mechanism that strikes the firing pin used to ignite the propellant.

Firing Pin: Also called a striker, the firing pin transfers the momentum of the hammer to strike the primer on a cartridge.

Sight: A gunsight is a fixed or adjustable optical device used to help a person aim a firearm. An iron, laser, dot, or telescopic sight helps your eye line up with the muzzle and target.

Accessories Rail: Straight mounting brackets used to support tactical accessories such as flashlights or laser aimers.

Bolt: A mechanical part that blocks the rear breech when fired and moves aside to facilitate reloading.

Main Parts of a Pistol

Pistols are a type of single-barrel handgun. Compact in nature, the pistol is wielded in one hand. Pistol sizes include subcompact, compact, standard, competition, and longslide styles. 

They feature common parts such as the frame, trigger, hammer, and other fire control components.

Grip: As mentioned above, the grip is the butt of the firearm, but in pistols, it also houses the magazine.

Magazine: A magazine is a type of ammunition storage that holds multiple cartridges that are fed automatically into the firearm. All guns except for revolvers or single-shot guns have magazines.

Magazine Release: A button or lever that releases a detachable magazine.

Magazine Well: Also known as magwells, the magazine well locks the magazine in place to be fed into the chamber.

Takedown Lever: A mechanism that holds the bolt, barrel, and slide, as well as allows the firearm to be disassembled.

Slide: The upper metal component that literally slides with the recoil. A slide can contain the firing pin and the extractor.

Slide Stop: Also known as a slide lock, the slide stop is a safety feature that locks the slide after shooting the last cartridge in a magazine.

Receiver: The part of the gun that contains all of the components of the firing mechanism.

Safety: A button or sliding mechanism is used as a safety feature to prevent accidental discharge of the weapon. A safety is usually located near the trigger or handgun handle.

Extractor: The part of the firearm that removes the spent shell casing out of the chamber.

Ejector: A spring mechanism that releases the spent casing through an opening.

Tang: Some grips have a curved protrusion near the top of the grip used to help the shooter manage the recoil and protect the hand from the slide mechanism.

Ammunition

Knowing your gun parts is well and good, but you must also consider the basic components of your ammo: the case, the primer, and the gunpowder.

Case: An ammunition case, usually made out of copper, brass, or steel houses the components of the projectile.

Primer: Primer is an explosive chemical compound that coats the rim of the case or the center of the casing base. When lit by a firing pin, the primer ignites the gunpowder.

Gunpowder: An easily flammable mixture of chemicals that converts to expanding gas when ignited.

Handgun bullets range in size, shape, and weight. For most situations, you’ll go with a soft or hollow point bullet, which “mushrooms” upon impact. Target practice bullets have flat or solid points to create a clear hole in the paper.

Here are the most common types of handgun bullets:

• Roundnose
• Wad Cutter
• Semi Wad Cutter
• Full Metal Jacket
• Hollowpoint

Choosing a Firearm

Now, which firearm do you need? The type of gun you need will largely depend on your life circumstances. If you are living in a rural environment, a heavy-duty firearm like a rifle can provide you with adequate protection and functionality for sporting. If you live in the city, however, a smaller handgun for home protection will do the trick.

Modern handguns vary in size, shape, color, and function. Each type of gun may feature different parts, but every firearm will always have its most basic elements to power the firing mechanism. Understanding every part of your piece will keep you and others safe.