Many people have childhood memories of firing a .22 rifle for the first time. If you’re one of these people who was introduced to hunting and guns through the low-powered .22 caliber, you already have some experience with rimfire ammunition.
If you’ve spent any time reading up on ammunition, you have probably come across the terms “rimfire” and “centerfire” when talking about ammo. While both types of ammo function the same way, they work a little bit differently.
To look at those differences, we first need to take a look at what’s inside your ammunition.
The Five Ingredients that Make a Cartridge
Regardless of whether you’re shooting centerfire or rimfire ammo, your cartridge is made of up the same five components:
- The bullet
Also, it’s important to note that the term “bullet” is a colloquial term that we call all ammunition. But technically speaking, the bullet is really just the projectile fired from the gun. This is why most firearms sites, including ourselves, refer to ammo as rounds or cartridges instead of bullets. That helps us to avoid unnecessary confusion when discussing topics around ammunition.
What’s the Difference Between Centerfire and Rimfire Ammo?
Despite being made up of the same components, rimfire and centerfire are quite different, and the biggest difference between the two types of ammunition lies in their names.
Rimfire bullets are ignited by striking the rim of the cartridge. And as you might have guessed, centerfire ammo is ignited striking the center.
By looking at the picture above, you can see just where the firing pin of each gun hit the primer. Notice how only one of them has an indention in the center.
The difference in how centerfire and rimfire ammo is ignited
Technically speaking, the only real difference between rimfire and centerfire ammo is their ignition systems. Centerfire cartridges have a primer concentrated in the middle of the cartridge base, whereas the primer in a rimfire cartridge is distributed across the entire base.
These days, rimfire cartridges are almost always low-powered, whereas centerfire ammo is not. But that wasn’t always the case. In the 19th century, rimfire cartridges were made in a number of different sizes, including the .56-56 and .58 caliber.
Rimfire cartridges were as popular as their centerfire counterparts up until the turn of the 20th century, when manufacturers discovered ways to produce centerfire ammo cheaper. Shortly afterward, centerfire cartridges became the standard type of ammunition.
But why are rimfire cartridges associated with weaker ammo?
Because the firing pin has to strike the actual cartridge of a rimfire round to ignite it, the cartridges needed to be thin enough to engage the primer. Because the same isn’t true for centerfire ammo, they could make cartridges using larger bullets and more gunpowder.
Of course, that wasn’t always the case. As we mentioned above, there were instances in the past where larger calibers were made using the rimfire design. But these days, centerfire ammunition is widely regarded as the more effective solution for more powerful rounds.
The discontinued .41 Short rimfire cartridge was a popular round in the mid-19th century.
Benefits of Rimfire Ammo
There’s a reason why so many people are given a .22 LR as their first gun – it’s easy to control, making it the ideal rifle to learn with.
Rimfire ammo is great for target practice and shooting small game like rats and squirrel. And best of all, it’s incredibly cheap. The average price-per-round of a .22 LR cartridge runs anywhere between a nickel and a dime, whereas your standard .223 round costs 30 to 40 cents.
Drawbacks of Rimfire Ammo
The downside of rimfire ammo is that you’re incredibly limited in what you can use it for. While there are cases of .22LR rounds being used in modern combat, rimfire ammunition isn’t the best choice for tactical situations because of its low power. That’s not to say that the .22 LR isn’t a lethal round – because it is – but it’s not the best choice for concealed carry or home defense.
Some other drawbacks of rimfire ammo include:
- No recycling loads: Hobbyists can’t reload spent rimfire cartridges.
- Duds: Sometimes the primer of a rimfire cartridge isn’t properly ignited, causing a failure to fire (FTF). Usually happens no more than once per 100 shots fired.
- Buildup: Rimfire ammo burns dirty and can damage your gun if it’s not properly maintained.
Available Rimfire Ammo Choices
Nowadays, rimfire ammo comes in two caliber sizes: .17 and .22. The most common type of rimfire ammo is the .22 Long Rifle (LR), which is what’s commonly used to hunt squirrel and other small vermin.
Here are the different types of rimfire ammo you’re likely to encounter:
- .17 HMR: A newer rimfire cartridge that’s slightly more powerful than the .22 LR
- .17 HM2: The Hornady Mach 2. Slightly smaller than the .17 HMR, but still more powerful than the .22 LR. It’s an uncommon round.
- .22 WMR: Winchester Magnum Rimfire. Larger and more powerful than the .22 LR, but not as powerful as the .223.
- .22 LR: One of the most popular rounds of all time. Commonly used to hunt pests.
- .22 Short: A round used in some revolvers and a handful of rifles. Not as popular as the .22 LR but some rifles will specific if they’re compatible with LR and Short cartridges.
From left to right: .22 Short, .22LR, .22 WMR, .17 HM2, .17 HMR
Our Rimfire Ammo Recommendations
When it comes to .22 LR rounds, ammo is cheap and easy to come across. You’ll have no problem choosing between a number of mid and high-range .22 LR rounds for your rifle or pistol.
.22 LR Ammo
If you need some ammo to take care of small varmints like rats and snakes, we recommend the GAME-SHOK Shotshell ammo by Federal.
Designed specifically for taking care of pests, Shotshell ammo fires #12 Shot pellets instead of an actual bullet. This makes the ammo an optimal choice when killing pests because you don’t have to worry about bullets ricocheting or hitting unintended targets when firing outdoors.
Another popular choice is the 36 Grain Hollow Point Copper Plated rounds by Winchester.
Perfect for any occasion, these rounds can be used to kill vermin around the barn, hunt squirrel, or practice shooting targets.
If you’re looking for ammo to use specifically for range training, we recommend CCI Standard Velocity 40 Grain LRN ammo.
Cheap, accurate, and effective, Standard Velocity rounds are perfect for shooting targets or simply learning how to operate your first firearm.
Other Rimfire Cartridges
Remington’s 17 Grain AccuTip-V .17 HMR rounds are another good small game hunting choice.
The downside is that they’re more expensive than the vast majority of .22 LR ammo. However, it’s accurate, dependable, and perfect for killing opossum, rabbits, and other small game.
Winchester’s 40 Grain .22 WMR rounds bring a little extra power than your .22 LR or .17 HMR cartridges.
Great for hunting small game, this round is also a popular choice among raccoon hunters as well.
Aguila 29 Grain CPRN .22 Short rounds are a good choice for range practice with your .22 Short gun. Just remember to check whether your .22 LR rifle supports this round or not, otherwise you could end up damaging your barrel.
The HM2 is not a common round, but if you do happen to shoot this cartridge, we recommend 17 Grain V-MAX by Hornady.
Accurate, reliable, and fun to shoot, the HM2 is great for hitting targets and shooting pests like prairie dogs and opossum.
Sometimes More Power Isn’t Necessarily Better
Despite being weaker rounds, rimfire cartridges are a great way to spend the day shooting guns without spending a lot of money on ammo. For this reason, we recommend that all beginners use rimfire ammo as they become accustomed to shooting guns and hunting