Keep Your Rimfire AR Running Right

By Brad Fitzpatrick

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shooter looking down the scope of an ar rifle

AR-style rifles are extremely popular, and while most shoot centerfire cartridges, there is a large and growing number of rimfire ARs as well. Newcomers might think an AR is an AR, but there are significant differences between centerfire and rimfire platforms. Understanding the basics of how their operating systems work is the first step toward making your AR-22 run more efficiently.

Blowback Vs. Direct Impingement

Most centerfire ARs utilize direct impingement gas systems that channel escaping gases through systems of different lengths to operate the bolt of the rifle. There are also piston-operated ARs that use a gas piston in place of the direct impingement system.

Rimfire ARs use neither. Instead, the vast majority of rimfire ARs utilize blowback actions. Simply put, the energy produced by firing the cartridge pushes back against the bolt and cycles the action. It’s a very basic but effective system, and rimfire rifle manufacturers have spent years perfecting the blowback design.

What Your Blowback Gun Needs

Even if you’re new to firearms, you’ll have no trouble keeping your rimfire AR running properly. There are really just two things a blowback-operated rimfire AR needs: proper maintenance and proper ammunition.

We’ll begin with maintenance, and I’ll break this into two separate steps: cleaning and lubrication. You’ll need to clean away fouling that builds up when you shoot your rifle. When fouling accumulates in the chamber, it can impede bolt cycling. A buildup of debris accumulated over hundreds of shots gums up the operating system and needs to be cleaned away. Concentrate your efforts on the chamber, including the bolt, and be certain to use a solvent designed to break up fouling for easy removal. Wipe the fouling away from the action and clean the bore.

Hoppes Universal Cleaning Kit

The next step is lubrication. Even clean actions that are completely dry (free of lubrication) might not run properly because the coefficient of friction within the action is too high. High friction interferes with normal operation, so when you clean your AR rimfire, be sure to add a thin layer of lubricant to the moving parts. The rails on which the bolt rides should also have a thin layer of lubrication added.

Note that I say “thin”—you don’t want to overlubricate the action. Some shooters get overzealous and soak the action with excessive lubricating oil, and this can result in gumming up the action—especially in cold temperatures. I prefer to apply the lubricant to a rag and then add it to the firearm rather than simply spraying lubricant into the action.

How often you need to clean your rimfire AR depends on multiple factors, but perhaps the most important consideration is ammunition. Some rimfire ammunition is dirty, producing excess fouling that shortens the time between cleanings. If your AR gets excessively dirty after firing just a box or two of ammunition, you’ll want to consider a different, cleaner load. CCI ammunition runs cleaner than many other rimfire brands, and Clean-22 ammunition’s polymer bullet coating keeps the action and the bore much cleaner than many other loads. Clean-22 High Velocity pushes a 40-grain polymer-coated bullet at 1,235 feet-per-second and consistently cycles 22 LR ARs.

Consistent Ammunition

Speaking of ammunition, you need a load that not only runs clean but will also provide consistent energy sufficient to cycle semi-auto actions. Blowback AR rimfires require a load with enough “push” to cycle the bolt, and while I’ve had blowback actions operate with .22 ammunition in the 800 foot-per-second velocity range, I’ve found more velocity and pressure typically results in more consistent performance. For that reason, it’s a good idea to invest in ammunition that is specifically designed to operate ARs.

female shooter loadding a magazine with a box of 22 LR sitting in the foreground.

There are few rounds better suited to this task than CCI AR Tactical. This load was designed to operate 22 LR ARs effectively, and with a muzzle velocity of 1,200 feet per second, it provides plenty of energy to cycle modern AR-style blowback actions. Like other CCI loads, it uses clean-burning powder which limits fouling and extends the period between cleanings, and the copper-plated 40-grain projectile reduces bore fouling and provides exceptional accuracy. Plus, the rounds carry enough energy for small game hunting and pest control.

The Ultimate Fun Gun

It’s hard not to enjoy shooting rimfire AR rifles. Recoil is minimal, and so is the relative cost of ammunition. With so many great rimfire AR options on the market right now, it’s the perfect time to invest in one. And, with a bit of care and attention, it’s easy to keep an AR rimfire running right.