Alternative AR Calibers

Alternative AR Calibers

Posted by STNGR USA on Oct 25th 2022

The AR 15 is truly a remarkable weapon. It’s easily the most modular weapon on the planet and the aftermarket is massive. The AR 15 is so modular you can easily chamber it in a wide variety of different calibers. I’ve gathered my Top 5 Alternative AR calibers to share with you today.

.22 Long Rifle

The 22 LR round is easily the most popular round in the world, as well as the most affordable on the market. It’s a relatively cheap plinking round designed for taking small game. It’s best used in an AR 15 as a training round when you are looking to cut costs. This is the easiest conversion and requires nothing more than a new magazine and a drop in bolt when using a 5.56/223 upper receiver.

This kit is perfect for plinking and affordable training. You can turn your favorite AR 15 into a kid friendly plinking machine in just a few seconds. The with the 22LR you have:

  • Ridiculously cheap ammo
  • Almost zero recoil
  • A quick and Easy conversion


When it comes to pistol caliber carbines the 9mm caliber is king. 9mm ammo is plentiful, cheaper than most rifle rounds, and offers plenty of magazine compatibility options. It’s not hard to find an AR 15 in 9mm that takes Glock, SIG, and S&W magazines. A 9mm AR is also very easy to suppress thanks to commonly available subsonic 9mm ammunition.

9mm ammo also allows you to use your rifle on ranges commonly reserved for pistols only. Pistol caliber carbines even have their own category in USPSA these days and the AR in 9mm is a perfect companion. With a 9mm AR you get:

  • An easily suppressed platform
  • Magazine commonality with handguns
  • A light recoiling and cheaper shooting gun.

300 Blackout

The 300 Blackout is the bell of the ball when it comes to alternative AR 15 calibers. It addresses several weaknesses of the 5.56 round and is the perfect caliber to coexist with. The 300 Blackout is a 30 caliber round which makes it legal to hunt in many states that do not allow 5.56 caliber rifles. Additionally, the round performs extremely well from short barrels making it a perfect round for AR 15 pistols and SBRs. Subsonic rounds are also common enough that suppressing the weapon is easy to do.

The 300 Blackout uses an overwhelming amount of parts as a 5.56 AR 15. This includes magazines, BCGs, uppers, lowers, and every piece of furniture out there. The 300 Blackout gives you:

  • Easily suppressed rifle round
  • Parts commonality with 5.56 AR15s
  • 30 caliber projectile with supersonic and subsonic round available.

7.62 x 39

The 7.62 x 39 is famed of the round of the AK 47 and putting it in the AR 15 seems not very kosher, but the round has become a favorite in the AR 15. It gives the short range, hard hitting power of the AK with the ergonomics of the AR 15 platform. The 7.62 x 39mm round requires special magazines, but will work with standard lowers and uppers as long as the barrel is the appropriate caliber.

The 7.62 x 39mm round is also the cheapest 30 caliber round on the market, making it perfect for hunting in caliber restricted states. The 7.62 x 39mm round is quite cheap even, sometimes cheaper than even 5.56. These round gives you:

  • Cheap 30 caliber round
  • Powerful, hard hitting performance
  • AK style performance with AR 15 ergos

224 Valkyrie

The 224 Valkyrie is designed to maximize the long range potential of the AR 15 platform. Most long range guns fall into the AR 10 category but the newly designed 224 Valkyrie gives you 1,000 yard performance in an AR 15 platform. This new round allows you to reach out and touch a target that’s way out there.

It’s a high performance cartridge with a relatively high cost. The newness of the cartridge and its design demands tight tolerances so it remains expensive compared to other AR 15 cartridges. It does give you:

  • 1,000 yard performance in a lightweight platform
  • Precision cartridge performance
  • Mild recoil and muzzle rise.

Going Alternative

Alternative AR calibers offer you massive potential beyond your common 5.56 AR 15. Each gives you the ability to try something new, do something different, and expand your AR 15 horizons. We each have our favorites and our reasons why, but at the end of the day we are all connected by the same platform.