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.
Not understanding that 100%? We’ll walk you through it in detail.
First…how does a bullet work?
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Parts of a Cartridge
A standard cartridge, or round, consists of four parts — the bullet, propellant, primer, and a case.
Keep in mind a “bullet” means just the projectile, not the entire cartridge. These components are all present regardless of 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.
(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.
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.
You can see the firing pin marks on the spent brass above. Again, centerfire hits the center primer while rimfire hits the rim.
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.
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 setup. 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).
.22LR Ammo In Stock
Check out our Best .22 LR Ammo for Accuracy, Plinking & Hunting guide.
- .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
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.
5.56 and .223 Ammo in Stock
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 setup.
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.
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.
Recommended Ammo
Looking for some centerfire or rimfire ammo? Check out our Best .22 LR Ammo for Accuracy, Plinking & Hunting…or our exhaustive Ammo & Reloading guides.
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.
42 Leave a Reply
Good overview Eric. Though I would suggest you add the differentiation between Boxer and Berdan Priming systems to the article. Also the fact that Boxer was developed in Europe and Berdan in the US, yet the US adopted Boxer priming and Europe adopted Berdan Priming (funny anecdote).
I would also add the difficulty in reloading Berdan brass (impossible without some specialty tools, and usually not worth the effort if you have the tools).
The Old Educator in me (yes, I taught school for a few years) always believes that when discussing a subject, one should always completely discuss all the aspects of the subject.
Just some suggestions on making a future "Primer" primer (pun intended) a little more complete.
I get the diff between center and rimfire shells but why are center fire guns restricted some places?
Usually Caliber Restrictions are done at ranges because the backstop is only rated for handling certain calibers. Our Municipal indoor range is limited to centerfire pistol only, no larger than .45, and no magnums (.22WMR and .17HMR are OK). That range has occupied the same building since the 1930's, but prior to 1972, it was .22 LR only. In 72, they first installed bullet traps made out of armored plate. Even then, only cast or swagged lead bullets were permitted. In the late 90s, they upgraded to ballistic curtains, and then we could use FMJs and HPs.
Even 3 out of the 4 nearby Outdoor Ranges are Caliber Restricted. .300 Win Mag is the limit for 3 of the 4. Only 1 allows up to .50 BMG.
Some municipalities may Caliber Restrict as an attempt to reduce crime. Is it successful? Not really.
I don't know what the current stats are, but from the 80's into the early 2000s, there were more deaths and wounds (accidental and intentional) attributed to.22 LR across the US, than any of the other caliber.
These are the reasons I was told. There may be a few more, but those are likely why the Caliber Restrictions are in place.
“Exactly”
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.
thanks dad but didn't you ask if the rim fire uses a different firing pin than the 38
Thank you, straight forward and concise.
Thanks for explaining it so clearly.
Thanks for the info. on CF & RF ammo. Important information. Thanks again.
Terrific explanation of the differences between rim and center fire. Very informative.
Great descriptions of the two types of cartritges. Made it easy to understand, thanks.
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.
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
Are they really proposing that???
So what is safer rimfire or centerfire
Curious as to why you didnt include a PRO and CON section for Centre Fire....
So you said the pros and cons of rimfire, but not center-fire, at least not that I seen using my phone.
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?
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.
Ok, thx
It has more sense now :D
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.
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?
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.
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
Hi Doug, I'd bring it back if you have any doubts.
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.
You are another part.
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.
...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.
Very nice article. Consider adding a couple of pics of the firing pins from both types of guns.
Thanks and great idea. I'll get some pictures the next time I take apart my 10/22.
Answered my question perfectly. Great article.
well written, thank you so much for the info!
You're welcome Shay!
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?
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.
Thanks for your work here, Eric. Great, concise explanation.
Thanks Jon!
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
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.
Can the same 22 pistol used Rimfire and Centerfire?
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.