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

Armasight Operator thermal riflescope
Armasight Operator thermal riflescope

New for 2026: Armasight Pro Series Thermal Platform

Armasight launches a professional-grade thermal-imaging platform designed to perform.

KelTec Launches KelTec Direct

KelTec begins its 35th anniversary celebration by launching KelTec Direct.

New for 2026: CVA Scout XP and XP-SB Rifles and XP Pistol

CVA expands its Scout line to include two single-shot rifles and a single-shot pistol.

Preview: Winchester After Hunt Dog Bed

Named after John Olin’s famed hunting dog, the King Buck product line exists within the larger Winchester Pet brand to showcase the company’s most deluxe offerings, and the After Hunt Dog Bed is a prime example of the line’s quality.

Review: CZ USA P10 Ported

CZ expanded its popular line of P10 handguns with a specially configured model that features integral barrel ports just behind the muzzle to aid in recoil management.

Keeping The Wilderness Quiet: Bergara's BTi30 Suppressor

Bergara joined the growing crowd of suppressor manufacturers in 2026 with its BTi30 design.

Interests



Get the best of American Rifleman delivered to your inbox.