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[Beginner’s Guide]: Rimfire vs Centerfire Ammunition

Want to know the difference between rimfire vs centerfire?

Rimfire and centerfire are two categories of primer ignition systems for ammunition cartridges.  

The firing pin in rimfire guns strikes the rim of the cartridge base to ignite a primer while in centerfire the firing pin strikes a center primer.

Rimfire vs Centerfire Primer Strike
Rimfire vs Centerfire Primer Strike

Not understanding that 100%? We’ll walk you through it in detail.

Confused Wahlberg
um….wut?

First…how does a bullet work?

Table of Contents

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Parts of a Cartridge

A standard cartridge, or round, consists of four parts — the bullet, propellant, primer, and a case.

Deconstructed 9mm Cartridge
Deconstructed 9mm Cartridge

Keep in mind, a “bullet” means just the projectile, not the entire cartridge. These components are all present regardless whether a round is a rimfire or centerfire.

In the grand scheme of things, all bullets work the same…the firing pin of the gun hits the primer which creates a tiny explosion.

That tiny explosion sets off the gunpowder which forces the bullet itself forward and out of your gun through the barrel.

Parts of a Bullet Cartridge
Parts of a Bullet Cartridge

(We got more details on this in How a Gun Works.)

The difference between the rimfire and the centerfire is where that primer is located.

Centerfire vs. Rimfire Appearance

The easiest way to tell them apart is to see if you can see a circular primer in the center at the base of the casing.

*Gasp*

The primer in the center = centerfire!

If you see a smaller cartridge with no overt primer, it is likely rimfire.

Rimfire vs Centerfire Cartridges
Rimfire vs Centerfire Cartridges

Different Ignition Systems

You can see that the names really make sense when you look at the ignition systems.

Rimfire ammo gets its name from the firing pin striking the “rim” of the cartridge to ignite the primer. While centerfire ammo is where the firing pin strikes the primer that is located at the “center” of the cartridge base.

Centerfire vs Rimfire Primer
Centerfire vs Rimfire Primer

You can see the firing pin marks on the spent brass above. Again, centerfire hits the center primer while rimfire hits the rim.

Rimfire vs Centerfire Primer Strike
Rimfire vs Centerfire Primer Strike

Common Types of Rimfire Ammo

Rimfire ammo is limited to smaller calibers since the cartridge walls need to be thin enough to be able to be crushed by the firing pin and ignite the primer.

Popular Pistol Calibers
Popular Pistol Calibers

The downside?

Well, the nature of the casing means it’s pretty much limited to small calibers. You have to have some relatively flimsy brass to handle the rimfire set up. As a result, the powder necessary to propel a larger bullet would blow the brass apart.

The most common type is the .22 LR (long rifle). Check out our Best .22 LR Ammo for Accuracy, Plinking & Hunting guide.

.22LR (CCI vs Winchester vs Super Colibri)
.22LR (CCI vs Winchester vs Super Colibri)
  • .22 Short: Used in some revolvers, not too popular.
  • .22 Long Rifle (LR): Most popular round in the world and the starting point for many shooters.
  • .22 WMR: Winchester Magnum Rimfire. Used to hunt vermin and is between the .22 LR and the .223 centerfire round.
  • .17 HM2: Hornady Mach 2: Higher power than the .22 LR but smaller. Didn’t really take off. The smaller brother of the HMR.
  • .17 HMR: Hornady Magnum Rimfire. Newer round that is flatter shooting and more powerful than the .22 LR
.22LR vs .17 HMR
.22LR vs .17 HMR

Pros of Rimfire Ammo

Cheap

.22 LR can be found for 5 to 10 cents while the AR-15 .223 round is between 25 to 40 cents each.

It is so cheap since it is easier to manufacture a thin-walled case with a flattened primer at the bottom.

Something Of a Poor
Hey, we all need to save a few pennies from time to time.

The downside?

Well, the nature of the casing means it’s pretty much limited to small calibers. You have to have some relatively flimsy brass to handle the rimfire set up.

As a result, the powder necessary to propel a larger bullet would blow the brass apart.  However, there has been some hoarding in the last few years which makes it a little difficult to find in stores and online.

Low Recoil

The .17 and .22 caliber bullets and a small amount of gunpowder make for extremely low recoiling firearms. Perfect for the beginner or for training.

Cons of Rimfire Ammo

Not Reloadable

The primer is inside the bottom of the case and so cannot be reloaded like centerfire rounds. But rimfire ammo is so cheap comparatively that it doesn’t matter.

Reliability Issues

Even with top-shelf ammo like CCI, I still manage to get 1 to 2% failures to fire (FTF) in my 10/22 rifle.

Fully Upgraded 10/22
Fully Upgraded 10/22

This is because, in manufacturing, the primer compound is “spun” at the bottom of the casing and sometimes does not make full contact with the entire rim.

Rimfire is great for range plinking and varmint hunting, but I would not trust it for personal defense.

Small Calibers

Again, because of its design, rimfire is stuck with small calibers. There are some exotic larger caliber rimfires out there but they are very rare.

Looking for some centerfire or rimfire ammo? Check out our Best .22 LR Ammo for Accuracy, Plinking & Hunting…or our exhaustive Ammo & Reloading guides.

22 LR Ammo
.22LR Ammo

What do you like best, centerfire or rimfire? Let us know in the comments! Want to read more on ammo? Check out our look at Brass vs. Steel.

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37 Leave a Reply

  • Commenter Avatar
    John

    the way my dad explained it to me when I was just a kid was this, he took a 22 long casing and a .38 special casing, both had been fired, and showed them to me and said:

    "if the casing needs to be hit on the rim of the back like this .22 its called rim fire. If the case has a separate part in the center, like this .38, and that's where it needs to be hit with the firing pin its called center fire."

    Thus ends the lesson. Dad was not one to spoon feed, he expected me to pick it up and learn about it but gave me a boost in the right direction first.

    October 13, 2021 12:24 pm
  • Commenter Avatar
    Linda Yeargin

    Thank you, straight forward and concise.

    September 7, 2021 4:26 pm
  • Commenter Avatar
    Kevin

    Thanks for explaining it so clearly.

    August 21, 2021 3:49 pm
  • Commenter Avatar
    Enrique Perez

    Thanks for the info. on CF & RF ammo. Important information. Thanks again.

    July 22, 2021 6:30 pm
  • Commenter Avatar
    Dave Bush

    Terrific explanation of the differences between rim and center fire. Very informative.

    July 6, 2021 1:12 pm
  • Commenter Avatar
    Forrest J Byas

    Great descriptions of the two types of cartritges. Made it easy to understand, thanks.

    June 20, 2021 11:21 am
  • Commenter Avatar
    EscapeFromNY

    Hi Eric, I was looking to purchase a Beretta 21 Bobcat built for .22LR, but thankfully after reading your article I learned that this ammo is rimfire and that you would not trust it for personal defense. Sooo, any suggestions on a small, light, reliable, centerfire pistol? p.s. After finishing my Hunter-Ed course I'll be signing up for your Gun Noob course.

    May 30, 2021 8:28 pm
  • Commenter Avatar
    Mark

    Great article. Reading thru the proposed gun confiscation law in Virginia I see that they are calling out center-fire weapons. Your last line indicated that there are some exotic larger caliber rim-fires. Seems to me these may see a huge increase in demand. Maybe you can do an article on advances in rim-fire materials, manufacturers etc. Txs

    December 6, 2019 8:16 am
    • Commenter Avatar
      Damion Roberson

      Are they really proposing that???

      April 15, 2020 9:49 pm
  • Commenter Avatar
    Austin

    So what is safer rimfire or centerfire

    August 21, 2019 9:35 pm
  • Commenter Avatar
    Scott Atlas

    Curious as to why you didnt include a PRO and CON section for Centre Fire....

    June 9, 2019 3:09 pm
  • Commenter Avatar
    Wyatt

    So you said the pros and cons of rimfire, but not center-fire, at least not that I seen using my phone.

    October 7, 2018 8:38 pm
  • Commenter Avatar
    Sandor

    Hello Eric, I have a few questions as well.
    You say rimfire is tipically for low caliber, but what about for example the 7.62x54R for szvd? That is not a small caliber (in my opinion), and pretty powerfull ammo.
    My second question is, is there any advantage/disadvantage in bolt mechanism between rimfire and centerfire types?

    December 13, 2017 1:58 am
    • Commenter Avatar
      Eric Hung

      Hi Sandor, you might be confusing rimfire (describes the primer) and rimmed (describes the casing). As far as I know, the 7.62x54R is a centerfire rimmed cartridge.

      Bolt will have less problems with a wider variety of ammo since some rimfire doesn't have the power to cycle semi's.

      December 14, 2017 1:03 pm
      • Commenter Avatar
        Sandor

        Ok, thx
        It has more sense now :D

        December 14, 2017 10:04 pm
  • Commenter Avatar
    Gold Nugget

    Hello Eric, just came across your nice website. I must add that I would never waste money on rim fire ammo. It's like trying to buy wet matches in a bathtub full of wankers.

    November 29, 2017 5:07 pm
  • Commenter Avatar
    Gail Meinhold

    OK, I'm an old lady but I do like to target shoot. I just bought a .22 that is a rimfire. What happens if I accidentally use centerfire bullets in the rifle?

    October 19, 2017 3:26 pm
    • Commenter Avatar
      Eric Hung

      They probably won't fit...but it wouldn't be good. Highly advise against using any ammo that is not for the specific firearm/barrel.

      October 26, 2017 2:24 pm
  • Commenter Avatar
    Doug Timmons

    I just bought yesterday 8/22/17 a 9 mm hand gun. The salesman sold me 9 mm centerfire bullets. My gun after I got home and read the manual is centerfire. Should I return the ammo?
    Doug

    August 23, 2017 12:41 pm
    • Commenter Avatar
      Eric Hung

      Hi Doug, I'd bring it back if you have any doubts.

      August 23, 2017 8:01 pm
      • Commenter Avatar
        gorbs

        If he's bought a centerfire gun and been sold centerfire rounds, yet is asking if he should return the ammo, I'd suggest that he's too stupid to own a gun. This is just a small part of everything that is wrong with America.

        October 3, 2017 2:25 pm
        • Commenter Avatar
          William Fold

          You are another part.

          June 29, 2019 3:16 pm
      • Commenter Avatar
        Guest

        Do you understand what Doug Timmons is asking? He bought centerfire handgun and sales man sold him centerfire ammo. That is correct, why should he return it? You should understand about guns and ammos better Eric.

        December 3, 2017 7:53 pm
        • Commenter Avatar
          Ansel

          ...yeah. I think that if the guy has any doubts he should talk face to face with someone about those doubts and clear up the issue.
          And this is best accomplished by bringing it back if he has any doubts. Some random guy on the internet can't confirm anything about the gun or ammo without a lengthy discourse. Faster and simpler to go talk to someone nearby.

          September 9, 2018 9:19 am
  • Commenter Avatar
    Jane

    Very nice article. Consider adding a couple of pics of the firing pins from both types of guns.

    July 7, 2017 9:06 am
    • Commenter Avatar
      Eric Hung

      Thanks and great idea. I'll get some pictures the next time I take apart my 10/22.

      July 7, 2017 3:39 pm
  • Commenter Avatar
    Will

    Answered my question perfectly. Great article.

    June 11, 2017 8:25 am
  • Commenter Avatar
    Shay Koosmann

    well written, thank you so much for the info!

    June 7, 2017 6:28 am
    • Commenter Avatar
      Eric Hung

      You're welcome Shay!

      June 13, 2017 2:08 am
  • Commenter Avatar
    salleh

    hello Eric

    Does Rimfire have the same meaning with non-center fire cased ammunition. ?
    What type of weapon using Rimfire ammunition cartridge ?
    Does any fully automatic weapon using Rimfire?

    February 11, 2017 6:57 am
    • Commenter Avatar
      Eric Hung

      Hey Salleh, thanks for your questions...I'll try my best. There might be another rarer class of ammo, but for modern cartridges there's rimfire + centerfire. There are both rifles and handguns that use rimfire. There's something called the "AM15" that is full auto .22LR.

      February 11, 2017 9:33 pm
  • Commenter Avatar
    Jon Woodard

    Thanks for your work here, Eric. Great, concise explanation.

    October 18, 2016 10:26 am
    • Commenter Avatar
      ehung

      Thanks Jon!

      October 20, 2016 3:41 am
  • Commenter Avatar
    Dan

    Hi Eric the other day a friend and I were plinking at the range with my 22 semi-auto and something weird happened. A different kind of bang and little pieces of something splattered my cheek when I realized the shell did not eject I racked the slide back looked in the chamber and the base of the cartridge was gone. The bullet fired and the only thing in the chamber was a hollow brass tube. We were shooting some bulk ammo. What would cause an explosion like that? Thanks, Dan

    August 26, 2016 7:38 pm
    • Commenter Avatar
      ehung

      Hi Dan, I'd definitely check the barrel first to make sure parts of the bullet isn't stuck in the barrel or else if you shoot again possibly bad stuff could happen. Otherwise...it might have been too much powder/primer or a bad case in that round.

      August 27, 2016 8:51 pm
  • Commenter Avatar
    leo

    Can the same 22 pistol used Rimfire and Centerfire?

    August 11, 2016 2:16 pm
    • Commenter Avatar
      ehung

      Hi Leo, short answer...no. You will have to match up the specific caliber of your gun to the ammo. As far as I know there's nothing that shoots both rimfire and centerfire.

      August 11, 2016 4:46 pm