New: CMMG 5.7x28mm to .22 LR Conversion Kit

by
posted on August 25, 2020
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
new-project.png (2)

CMMG has expanded its lineup with the addition of the Mk57 .22 LR AR Conversion Kit. Now, you can transform a CMMG 5.7x28mm upper receiver group into a .22 LR by swapping the bolt-carrier group and pairing with an AR-15/Mk4 lower receiver. Add in a dedicated CMMG .22 LR magazine, and you are ready to shoot rimfire.

The Mk57 .22 LR Conversion Kit is designed to be used with all existing CMMG Mk57 5.7x28mm upper receiver groups and bolt/barrel combinations, when paired with any AR-15/Mk4 lower receiver. Plus, no tools are required for installation.

Each kit includes the new .22 LR bolt-carrier group, and the choice of one or three 25-round magazines. In addition, CMMG has Mk57 5.7x28mm complete uppers available, in 5-, 8- and 16-inch barrel lengths.

MSRP ranges from $199.95 to $229.95, depending on the how many magazines you choose to purchase. Something to note, this kit is not compatible with Mk57 lower receiver groups or 5.56mm/.223 Rem. uppers. Learn more at cmmginc.com.


See more: Review: CMMG Resolute Mk4 PCC 9mm

Latest

Usashooting 2025Sept 1
Usashooting 2025Sept 1

U.S. Shotgun Team Reigns Supreme in 2025 International Season

Team USA’s shotgun athletes have captured 34 international medals in 2025, showcasing excellence from Olympic legends to junior stars

Review: Springfield Armory SAINT Victor 5.56 Rifle

Springfield Armory’s SAINT Victor 5.56 is loaded with enhancements that make it a strong contender as an all-purpose, AR-style rifle

Remington’s .22 Short Rimfire Ammo is Back

Remington brings back the .22 Short rimfire with updated loads for plinking, pest control and beginner training.

SK Customs Unveils ‘Kingdom of Atzlán’ Colt 1911 Series Honoring Aztec Heritage

SK Customs’ new .38 Super Colt 1911 handgun series blends Aztec mythology with handcrafted firearm artistry

Drew Cup Selection: U.S. Juniors Set Sights on Prestigious International Smallbore Showdown

The 2025 Drew Cup brings elite international smallbore competition to U.S. soil, where junior shooters compete for national pride via a postal qualifier

Competitors’ Corner: September 2025

Highlights from the September 2025 issue of Shooting Sports USA, the NRA’s competitive shooting journal

Interests



Get the best of Shooting Sports USA delivered to your inbox.