How Does a Bullet Work?

As simple as modern ammunition may look on the outside, there are a few things that go on the inside cartridge that make our guns go bang. Let’s talk about the different types of cartridges that you will encounter in the firearms world and how they function. Let’s get into how a bullet works.

Components

In general, you will find that most cartridges share the same four major components: a case, primer, powder, and projectile.

There are two main types of ammunition: rimfire and centerfire. One of the most noticeable differences between the two is the primer. rimfire and centerfire cartridges have primers that differ in location on the case, the construction of the primer, and where the firing pin of the weapon strikes the back of the cartridge to ignite the round.

How a Bullet Fires

It’s difficult to describe how a bullet works without a good visual. Check out this one by NetGrook

NAVIGATION

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1.

A cartridge is loaded into the chamber of the firearm

2.

The action is closed/pulled back and the firing pin is held back under tension

3.

The trigger is pulled, releasing the firing pin, striking the primer causing a small explosion

4.

The explosion from the primer ignites the gunpowder, causing hot gasses to rapidly expand inside the cartridge and propel the bullet down the barrel

Centerfire cartridges consist of a casing (Steel, brass, aluminum, polymer), a bullet, gun powder, and a primer in the center of the cartridge in the rear.

• The casing contains the powder, primer, and bullet all enclosed in one cartridge
• The primer is what is struck by the firing pin to ignite the gunpowder
• The gunpowder is what is ignited to propel the bullet out of the cartridge
• The bullet is the projectile that flies out of the end of the cartridge upon ignition

Centerfire cartridges consist of a casing (Steel, brass, aluminum, polymer), a bullet, gun powder, and a primer in the center of the cartridge in the rear.

The casing contains the powder, primer, and bullet all enclosed in one cartridge

The primer is what is struck by the firing pin to ignite the gunpowder

The gunpowder is what is ignited to propel the bullet out of the cartridge

The bullet is the projectile that flies out of the end of the cartridge upon ignition

Rimfire cartridges consist of the same components of a centerfire cartridges, but the primer runs along the complete rear of the case. This is because the firing pins in rimfire actions will strike the rim of the cartridge, not the center to ignite the primer.

Shotgun cartridges are another variation of centerfire rounds, but instead of a single, shaped bullet, most shot-shells have metal shot or slugs inside of a plastic casing or hull. A shotgun shell is composed of the plastic case (or hull), gun powder, shot, primer, and the wad (A paper or plastic piece that aids in pushing the shot out of the barrel consistently).

• The case is designed to hold all components of the shotgun shell in place. It also has a brass or steel head attached at the end that houses the primer and powder.
• The primer is located at the rear of the cartridge, it is made up of an anvil, primer cap, and priming compound. When struck by the firing pin it creates a small explosion and ignites the powder.
• The powder is what is used to propel the shot after being ignited by the primer by creating pressure from rapidly expanding gasses as a result of the powder burning.
• Shot is  what is propelled out of the shell and down the barrel of the shotgun towards the target.
• The Crimp is how the shot is kept inside of the shotgun shell. It is simply a fold at the end of the shotgun shell.
• The wad is a small disk or cup that is used to keep the shot separate from the powder and to help seal the gases from the propellant to help launch the shot out of the shell.