What Is the Largest Caliber Rimfire?

Rimfire ammunition is a metallic firearm cartridge with a hollow rim sticking out of the base.

Rifles and handguns use rimfire and are measured in caliber, which is the diameter of the barrel’s interior expressed in millimeters (10mm) or hundredths of an inch (.22 cal).

The largest caliber rimfire is a .22 cal, which is the most common form of ammunition sold today. .22 cal rifles, revolvers, pistols, and shotguns are ideal for hunting and shooting sports competitions, with the .22 long rifle particularly popular for short-range training thanks to its minimal recoil.

Let’s explore more of the largest caliber rimfire guns and how they work.

Table of Contents

What does “caliber” mean?

Caliber measures the diameter of the bore, which is the technical term for the inside of the gun barrel.

Typically, caliber is measured in millimeters or hundredths of an inch, such as with the .22 cal rimfire, which is the largest caliber on the market.


Cartridges are purchased based on the caliber, as they need to be the right size for the gun to fire properly.

Caliber is measured from land to land, which is the raised rifling portions between the interior grooves.

Licensed gun retailers and buyers select guns based on the caliber, the cartridges it holds, and the overall design.

All of these factors determine the gun’s power and accuracy.

What does rimfire mean?

Rimfire is used to describe a cartridge with the primer mixture around the outer edge of the base.

Primer is the explosive substance that ignites upon force to detonate cartridge powder. Rimfire cartridges differ from centerfire, which have a cup in the middle of the cartridge case base.

If you look at a rimfire cartridge and a centerfire side by side, you’ll see that rimfire ammo looks much smaller, as there’s no primer storage in the middle.

This means rimfire cartridges ignite once the firing pin hits the rim, while centerfire cartridges ignite when the firing pin hits the center.

Centerfire ammo has higher velocity and pressure, making it a popular option for self-defense.

rimfire ammo

However, rimfire ammo remains a go-to choice for reduced recoil, as these guns are easier and often safer to operate.

What is a .22 cal rimfire?

A .22 cal rimfire, also known as a 5.6mm caliber, is the largest and most common bore diameter for firearms.

This caliber is often used in long rifles and air gun pellets. .22 caliber has a very long history, having been used in the late 1800s, throughout the World Wars, and all the way through the present day.

Some of the most famous .22 cal rimfire weapons include the .22 BR Remington, often used for benchrest shooting and hunting vermin, and the .22 Winchester, introduced in the late 19th century.

The .222 Remington was the first rimless cartridge made for commercial use in the U.S., and since its introduction in 1950, it’s been a top choice for gun enthusiasts.

Remington ammunition remains one of the leaders in the firearms industry, with the .22-250 Remington another well-known .22 caliber.

It offers a high-velocity cartridge and minimal recoil for small game hunting.

What are .22 cal rimfire firearms used for?

22 caliber rimfire rifles

.22 caliber rimfire rifles are used across shooting sports, as there are short and long styles for all sorts of hunting.

Although .22 cal rounds may cover shorter distances at lower velocities than more high-powered ammunition, they remain incredibly popular for sport and self-defense.

Hunters who need more control and less recoil often opt for .22 caliber rimfire rifles for an accurate shot.

Target shooting and other competitions also make good use of .22 cal firearms with their sturdiness and reliability.

Are .22 caliber rimfire rifles dangerous?

Like any firearm, .22 caliber rimfire rifles can cause serious damage, particularly when fired at close range.

Unfortunately, these guns run rampant in some of the world’s most dangerous cities, and with the rise of assault rifles and automatic pistols, gun violence is a sad reality not just in the U.S. but around the world.

While .22 caliber rimfire rifles are often referred to as rabbit rifles because they are used for hunting small game, they are actually responsible for the most gun deaths, as outlined by GunPolicy.org.

Many high-profile mass shootings involve these rifles, so gun safety advocates are actively working to raise awareness and enact policy change that keeps these rifles out of the wrong hands.

What are the different parts of a .22 caliber rifle?


Whether it’s a .22 caliber rimfire rifle or a similar firearm, there are three main rifle parts to know about: the stock, barrel, and action.

The stock is what you hold and aim with, while the barrel is the rifled or smooth metal tube which the charge or projectile is fired from.

The action is the part that holds the ammunition and fires cartridges.

In addition to these basic components, a .22 caliber rifle also has a rectangular or cylindrical bolt that moves within the receiver to keep the cartridge case supported throughout firing.

In a repeating rifle, ammunition passes from the magazine through the bolt feed and into the chamber.

There is also the muzzle where the bullet comes out of the end of the barrel. With a rifle, there is a fair distance between the muzzle and the stock, which is the back frame that supports the barrel.

Remember, a .22 caliber rifle and similar rifles are often called long guns, designed for shoulder firing with much greater size than a handgun.

How can you measure a gun’s caliber?

To identify a gun’s caliber, you can look near the receiver or barrel, where the caliber is typically stamped into the gun.

gun's caliber

With some firearms, this stamp is near the breech end of the barrel where you load bullets, serving as an important reminder of the gun’s power and strength.

On a standard .22 caliber hunting rifle, the manufacturer usually stamps the caliber on the twisted end of the barrel.

Sometimes the stamp may just have the model number, which can be entered with the serial number on the brand’s website to confirm the caliber.

Should you choose rimfire or centerfire?

When shopping for a firearm, you have the choice of rimfire or centerfire cartridges. One of the main reasons why a lot of people choose rimfire is the low cost, as these cartridges are cheaper to make and therefore cheaper to buy as a consumer.

Fewer materials are needed to produce rimfire cartridges, making them ideal for training and beginners who need a lower caliber to start anyway.

However, rimfire cartridges have a few cons, mainly that they are not reloadable and are limited to smaller calibers and shorter distances.

rimfire cartridges

For long-distance shooting, centerfire ammo is more dependable, as it can be used by all gun sizes.

The primer is in the center of the cartridge, so it’s directly struck by the firing pin, and reloadable, unlike rimfire.

Essentially, if you want more control and more cost-effective cartridges, rimfire cartridges remain a popular choice with many hunters and trap shooters.

If you’re a more experienced shooter and happy to spend more on ammo for shooting over long distances or using heavier guns, then centerfire is a good way to go.