The world of ammunition can be confusing and it gets more confusing when we add the different types of cartridges to what we have to remember.
The differences in bullets don’t just rely on the caliber or powder load but they include the overall cartridge itself. These differences determine how some guns can be used or practiced with.
So let’s go over the two major cartridge styles and what makes them different.
Centerfire vs Rimfire: The Key Differences
Cartridges or the bullets you load into your gun are a combination of four major parts: the bullet/projectile, the powder charge, the case, and the primer.
The case and primer can take on two major variations known collectively as rimfire and centerfire cartridges.
Both work on the same principle of ignition but reach that goal in different ways. Because of the difference between centerfire and rimfire they are not interchangeable.
The history of these two designs is a little convoluted so let’s look at the cartridges themselves.
Cartridges and History
Conceptually the oldest cartridge design we have are centerfire cartridges but rimfire cartridges were the first commercially viable option.
Rimfire ammunition was first invented in 1845, since then there have been dozens of different variations of the cartridge style. Some are still in use today with things like .22 Long Rifle and .17 HMR being some of the more popular options.
Centerfire on the other hand became commercially viable in 1855. It then went on to eclipse rimfire as the most popular type of cartridge and is the most commonly used cartridge type.
Since both of these cartridges have been living in some form of harmony for over 100 years let’s look at the differences. The first difference is their appearance.
Centerfire and Rimfire Appearance
The appearance of a cartridge is how you are going to be able to see if a cartridge is either a rimfire or centerfire cartridge.
Your primary focus will be on the base of the cartridge. This is because the ignition method of the bullet is at the base of the cartridge.
The front or bullet portion of the cartridge can vary across the different calibers and will not help you determine whether or not it is a centerfire or rimfire round.
The major difference will be if there is a small disk in the center of the bottom of the cartridge. If there is a noticeable disk there, it is a centerfire cartridge.
This disk is the primer. It is what the hammer or firing pin hits to detonate the powder charge. There are some different variations of this which we’ll cover later.
The center primer is featured on cartridges that feature a rim around the base of the cartridge and no rim around the base of the cartridge.
This is important because rimfire rounds feature a prominent rim around the base of the cartridge and can only be distinguished visually by the lack of a central disk on the bottom.
Rimfire rounds tend to be small in modern applications in addition to having that rim. However, this can be misleading because there are multiple centerfire cartridges with a pronounced rim. Always check for that center primer if you’re unsure if the cartridge is centerfire or rimfire.
This brings us to how these two types of cartridges ignite their powder charge.
Ignition Systems
The ignition systems of these two types of cartridges are the real reason why these cartridges are not interchangeable. This comes down to where the primer is placed and is either on the rim or in the center of the case.
This creates some nuances so we’ll look at each individually.
Rimfire
Rimfire cartridges feature the whole base of the bullet as the primer. The priming compound is located in the rim around the base of the case. This means that a rimfire gun has to hit the edge of the rim to detonate it.
Because this can be a finicky process, most rimfire guns feature a two-pronged firing pin that hits two different sides of the rim for more consistent ignition. This means a rimfire gun cannot be dry-fired repeatedly without damaging the firing pins.
Centerfire
Centerfire cartridges feature a single primer in the base of the bullet. These come in two varieties: Boxer and Berdan primers.
These variations work similarly in that they both drive the primer’s ignition into the powder charge to set off the round. The only real difference is that the Boxer primer has one “flash hole” to channel the ignition and the Berdan has two “flash holes.”
Since the primer is centrally located it is usually safe to dry-fire a centerfire gun since the firing pin will hit nothing but air. This varies from model to model and is affected by the quality of the gun. But most quality firearms can be dry-fired thousands of times without negative effects. It is recommended to use a snap cap if you plan to extensively dry-fire your gun in training.
Pros and Cons for Rimfire vs. Centerfire Ammo
As with anything, there are limitations to these types of cartridges, but is there anything you need to know when selecting a cartridge type to use?
Yes, so let’s look at the pros and cons of each.
Centerfire
Pros
Centerfire cartridges are the most widely used rounds on the market today. If you have a rifle, pistol, or shotgun you probably have used a centerfire cartridge or shell at some point.
Centerfire rounds are very reliable and allow for a wide variety of loadings to be used. Everything from basic ball ammunition to specialty self-defense and hunting rounds use centerfire cartridges.
These types of cartridges can be very accurate and are widely available in most firearms models on the market today.
Most of your options for serious use are going to be centerfire cartridges.
Cons
The only real downside to centerfire cartridges is that they are more expensive than modern rimfire rounds.
This comes from the slightly more complex design and the wider variety of calibers that centerfire cartridges come in.
Rimfire
Pros
Rimfire ammunition is low-cost and widely available around the world. It is perfect for pest control and very light hunting roles as most of the rimfire calibers today are designed for small game.
This also means it is great for teaching new shooters how to use firearms while getting them used to shooting a gun.
The low cost also means you can spend more time training with live ammunition without the higher cost of using centerfire ammunition.
Cons
While rimfire ammunition is great for training there are numerous drawbacks to these types of cartridges.
The first major issue is that rimfire ammunition is unreliable. Even with multiple firing pins, it is not uncommon for rimfire cartridges to not go off. This is a result of the manufacturing process and is caused by the primer distribution not being perfect.
This leads to multiple duds in a package of rimfire ammo. The unreliable ignition of these types of cartridges is one of the reasons why it was not as widely adopted as centerfire cartridges.
On top of this, you cannot reload rimfire cartridges. Because of the construction of the case, reloading a rimfire cartridge is impossible since you would have to replace the whole base of the case instead of a small primer.
When to Use Centerfire vs Rimfire
Each of these types of cartridges has its place, but determining when to use them can be problematic.
If you want to use rimfire cartridges they are best used as a supplement to your regular training.
Additionally, they can be used for hunting small game and pest control if you’re in a region where things like squirrels and prairie dogs are a problem.
For everything else, you can find a centerfire cartridge to fit your task.
Self-defense, hunting, and shooting sports all focus primarily on the use of centerfire cartridges. These are the better options for hard use and long-range shooting when compared to rimfire ammunition.
This comes down to the fact that rimfire ammunition today tends to be small diameter, low-pressure ammunition like .22 Long Rifle. These types of rounds do not have the energy or powder loads to deal with medium to large game reliably in addition to dealing with assailants.
This relegates rimfire to practice and pest control roles since the requirements for success are lower.
Recommended Ammo for Centerfire and Rimfire
Every round has a task that it can excel at, but for general uses, there are some things to keep in mind.
The factors to keep in mind are availability, intended use, and cost.
Today many of the centerfire and rimfire options have been pared down to a handful of rounds for each.
For rimfire, your best options are .22 Long Rifle and .17 HMR. These can be used effectively for pest control without too much of a financial burden.
For centerfire ammunition, there are more options. In terms of semi-automatic handguns, the best options are 9mm, .45 ACP, and in some cases 10 mm. Rounds like .380 ACP or more boutique rounds have their place but not if some of the major options are available.
In terms of revolvers, your best options will be in .38 Special, .357 Magnum, .44 Special, and .44 Magnum if you are going for common calibers.
For rifles, rounds like 5.56×45 and 7.62×51/.308 are good choices. You can also select 7.62×39 in addition to more specialty rounds like 6.5 Grendel. These choices will be affected by what you want to do with them and how available they are in your area or where you purchase your ammunition.
For shotguns, you will be choosing mostly from 12 gauge, 20 gauge, and some .410 options for your common shotgun types.
Which is Better: Rimfire or Centerfire?
While there is always the question as to which round is better, this time there is a more definitive answer.
Centerfire cartridges are better in most cases than rimfire cartridges. This is because they are reliable, widely available, and cover more ranges than rimfire.
Does this mean you should not use rimfire at all? No. But you should be aware of the limitations rimfire ammunition has. This applies to your preferred centerfire ammunition as well.
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