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

Chiappa Rhino 60 DS revolver in 10 mm Gun of the Week
Chiappa Rhino 60 DS revolver in 10 mm Gun of the Week

Gun of the Week: Chiappa Rhino 60 DS Revolver in 10 mm

Chiappa has launched a large-frame version of its unique revolver, including one chambered in 10 mm.

The Armed Citizen® Feb. 20, 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: Bergara B14 Stoke Rifle

Fit, comfort and precision for those that seek top-shelf performance—but need a step-stool to get there…

NFA Sales Up 121 Percent In January

Following the implementation of $0 tax stamps as of January 1, NFA sales skyrocketed in January, leading many to dub 2026 as the "Year of the Suppressor."

Rifleman Review: Smith & Wesson CSX E-Series

Smith & Wesson's pocket 9 mm gets some upgrades.

The Hush-Points: Hi-Point Introduces Centerfire Pistol & Rimfire Suppressors

Long-known for making affordable guns, Hi-Point Firearms has branched out this year to make affordable suppressors.

Interests



Get the best of American Rifleman delivered to your inbox.