Editor’s Choice: CMMG 5.7 mm Conversion Kit

by
posted on May 19, 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. **
cmmgkit.jpg

CMMG has tapped into a cartridge that has long been a niche round for a select few enthusiasts: the 5.7x28 mm FN. The cartridge underwent a recent resurgence with the launch of the CMMG Mk57 Banshee in 2019 and received a bigger boost with the 2020 launch of the Ruger-57.

Now CMMG proves that it wasn’t finished with the 5.7 mm by rolling out a conversion kit for today’s AR-15 rifle owners. The Mk57 Banshee fed from Five-SeveN magazines, requiring added investment for anyone not already sitting on a stock of them.

However, the Mk57 AR Conversion Kit provides an opportunity for owners of mil-spec AR-15 lower receivers to get in on the 5.7 mm fun. The conversion 
includes a STANAG-size magazine that provides a reliable feeding platform for the company’s 5.7x28 mm FN upper receiver.

Best of all, these proprietary magazines hold 40 rounds each, providing twice the capacity of FN Five-SeveN pistol magazines. For more information on these CMMG 5.7 Conversion Kits, visit
cmmginc.com.

Latest

Henrylasr 01
Henrylasr 01

The Lever Action Supreme Rifle: Henry's 21st Century Lever Gun

The Henry Lever Action Supreme Rifle (LASR) is a step away from the company’s traditional-styled lever-actions, providing a number of features that carry the lever gun into the 21st century.

The Seekins Precision SIC: A Modular Rifle for Special Operations Use

Originally designed for a SOCOM military contract, the Seekins Precision SIC is designed for anyone who wants extreme long-range accuracy.

I Carry: Taurus TX9 Compact in a Galco Holster

In our latest "I Carry" segment, we pair the new Taurus TX9 Compact with a leather Stow-N-Go holster from Galco, Inc. This compact, concealed-carry kit is rounded out with an Xolotl automatic knife produced by CRKT.

The Armed Citizen® March 13, 2026

Read today's "The Armed Citizen" entry for real stories of law-abiding citizens, past and present, who used their firearms to save lives.

Review: Canik USA MC9 Prime

Canik USA built out its concealed-carry handgun lineup with the MC9 Prime, which is a larger, yet still slim, CCW gun that sits in the same category as other upsized micro-compacts.

U.S. Army Awards Mossberg Contract for Additional 590A1 Pump-Action Shotguns

The U.S. Army has awarded O.F. Mossberg & Sons a contract for approximately $11.6 million dollars to supply the U.S. Army with additional Mossberg 590A1 pump-action shotguns.

Interests



Get the best of American Rifleman delivered to your inbox.