Converting an AR-15 to Chamber .22 LR

This conversion makes for a fun gun that’s less expensive to shoot, and installation is quick and easy.

Converting an AR-15 to Chamber .22 LR

Ammo shortages bring unwelcome baggage. They arrive unannounced, increase stress, cause confusion and add financial strain. Surviving one unscarred can be a challenge for any Tactical Retailer. 

A remedy for the parade of cartridge-supply vanishing acts has yet to be determined by the industry’s finest. Ammo shortages spawn from a variety of sources, defy simple solutions and are unavoidable in today’s gun business. 

When they strike, unless you have the budget and space to maintain an enviable store inventory “just in case,” some of your customers take their business elsewhere. Odds are good they won’t find fodder there, either, but that once-loyal patron could decide they’ve found a better, friendlier place to shop. 

You can’t keep someone from browsing a competitor’s selection, although you can reduce the reasons for doing so. There’s sometimes plenty of rimfire around when 5.56 NATO and .223 Rem. vanish from the shelves, and if there’s not, .22LR is the round customers are most likely to have large stockpiles of — so why not offer bolt carrier group replacements and magazines that convert an AR-15 to chamber .22 LR? Better yet, offer the value-added service of installation.

It’s fast and easy, and because the platform and manual of arms doesn’t change, it allows owners to continue drills and the practice it takes to build potentially lifesaving muscle memory. The kits aren’t overly expensive, and no special tools are required to get it done. Expect to invest only a few minutes — if that long — right at the counter.

Not all conversion kits are compatible with every AR-15 made, so study specifications before making any product recommendation. In rare cases, the trigger group can cause stoppages, so inquire if the owner has installed an aftermarket version.  

As always, the steps begin with those that maintain safety during the process. Keep the gun pointed in a safe direction at all times. Ensure the safety is engaged. If not, do so.

Remove the magazine and place it away from your immediate work area. Run the charging handle back and check that no cartridge remains in the chamber. Remove any you find, then double check the gun is clear. Use a flashlight if necessary. 

Once you’ve made the proper product choice, open the kit, inventory parts and consult directions. Inspect the bolt-carrier group replacement carefully. Any burrs or imperfections can impede reliable operation. The time to discover problems is early, rather than sacrificing the time it takes to encounter that roadblock. 

The chamber end of that bolt-carrier group replacement has identical dimensions as an unfired 5.56 NATO case. Most kits ship with it protected by a rubber sleeve to prevent bending and knicks. Remove it and inspect the “case” surface carefully. It needs to glide into the AR’s chamber smoothly — just like a fresh cartridge — without scarring the gun’s surface. 

Obviously 5.56 NATO magazines can’t handle .22 LR ammo. The conversion kit will contain at least one magazine designed for the rimfire, and in some cases three. Inspect these as well, making sure they are cosmetically satisfactory and that the followers glide smoothly. 

When satisfied that the kit arrived complete and in good shape, now you’re ready to begin work on the AR. First remove the back takedown pin. In the case of captive versions, push it out as far as it will travel.

Leave the front pin in its assembled position. Rotate the upper receiver away from the lower and remove the 5.56 NATO or .223 Rem. bolt carrier group and charging handle.

Now insert the bolt-carrier group replacement using the old charging handle. Be careful that the extension emulating a 5.56 case glides into the chamber smoothly. Do not force it, and stop and clean if it feels the least bit gritty during this process. 

After the bolt-carrier group replacement and charging handle are fully inserted, you’re ready to reassemble. Rotate the upper and lower receivers back together, insert and fully seat the rear takedown pin, and the gun’s back together.

Function-test at the charging handle, but keep in mind the distance required drops significantly because a .22 LR is a lot shorter than a 5.56. Work it and ensure the safety rotates properly. Reserve trigger work for live fire at the range (unless you happen to have a .22 LR snap cap on hand) and recommend the owner test fire soon, if not immediately.

Insert the magazine(s) and ensure they go in snugly and drop freely. Now you’re ready to hand the gun back to the owner, along with original parts.

If you have time, demonstrate how quickly they can turn their AR-15 back into its 5.56 NATO configuration. Don’t forget to mention which section of your store is well stocked with rimfire, too.  

Photos by Sagi

One—Keeping the gun pointed in a safe direction, engage the safety if it’s not already on safe. 

Two—Drop the magazine and remove it from your immediate work area.

Three—Work the charging handle back and check that no cartridge remains in the chamber. If there is one, remove it. Then double check the chamber is empty, using a flashlight if necessary.

Four—Open the package and inspect the condition of the bolt carrier group replacement. Look for burrs and marring that can impede reliable cycling.  

Five—The chamber end of the bolt-carrier group replacement has identical dimensions as an unfired 5.56 NATO case. Because it needs to glide smoothly into the chamber, it usually ships wearing a rubber sleeve to prevent damage. Remove the protective covering and make sure there are no bends or scars.

Six—Inspect magazines for blemishes and ensure the followers glide smoothly.

Seven—Remove the back takedown pin from the lower receiver. In the case of captive versions, push it out as far as it will travel.

Eight—Rotate the receivers apart and remove the original bolt carrier group. You will be using the same charging handle.

Nine—Insert the new bolt carrier group replacement with the old charging handle. Be careful that the extension that emulates a 5.56 case glides into the chamber smoothly. Don’t force it, and if necessary, clean the chamber and aftermarket unit to prevent bending or marring. 

Ten— Once the new component and charging handle are fully inserted, rotate receivers and insert the takedown pin fully. Now you can function test, keeping in mind the charging handle throw is now .22 LR length, not 5.56. Work it several times, insert the magazine(s) and make sure they go in cleanly and drop freely, work the safety, recommend the customer test fires soon, if not immediately, and you’re done.


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