In our classes we get a lot of questions about the differences between rimfire and centerfire ammunition. In this article, I will talk about what they are, how they differ and why you should care.

I discussed this a bit already in another article, but since repetition is key I thought it would be a good idea to give its own treatment. The difference between rimfire and centerfire ammunition is very simple: the location of the primer. In centerfire ammunition, the primer compound is located on a small, round primer that is attached (for lack of a better term) to the bottom of the case. Because the primer is in the center of the case, it’s centerfire ammunition.

Rimfire ammunition is different. Because rimfire ammunition generally refers to .22 caliber ammo (very small for you new shooters), the case is way too small to install primers in the center. Instead, manufacturers inject the priming compound into the bottom of the case and spin it around at a very high speed so the compound sticks along the inside rim of the case.

Rimfire Considerations

There are a few special issues to keep in mind when dealing with rimfire. They are by no means reasons to not use rimfire firearms, but consideration should be given when choosing to purchase or train with them.

Is Rimfire Ammunition Unreliable?

I get this question a lot as well. Because of the way primer is put into cases, rimfire ammo does have a more significant number of misfires than with centerfire cartridges. This issue is by no means an epidemic, but be aware that with rimfires you will see more misfire malfunctions. Does that make them unreliable? Not at all; you should not really be using a .22 for anything other than practicing, anyway.

Dry Firing with a Rimfire Firearm

Dry firing is a method of practicing your shooting fundamentals without using any ammunition. It’s a great way to work on trigger control, grip, sight alignment, etc… without having to go to the range.

But beware.

You should not dry fire with a rimfire firearm unless you are also using snap caps. This is because the hammer/striker/firing pin on rimfire firearms are very small and sensitive, and will wear down or break if they do not have a cartridge to hit against.

I hope this clears up some of the confusion. It’s not an incredibly difficult subject to tackle, but it is something that people should be aware of.

Special thanks to Mike from Tanners Brass for use of the photo at the top of the article!