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

Gotw Savage Axis 2 Pro 1
Gotw Savage Axis 2 Pro 1

Gun of the Week: Savage Arms Axis 2 Pro Western

Savage Arms has a whole new line of Axis rifles to suit the needs of a new generation of hunters and shooters, all loaded with premium features, and we took a closer look at the company's Axis 2 Pro Western.

Bookshelf: Rifle Cartridges for the Hunter

Richard Mann's latest book offers all the color of hunting stories with plenty of practical information, to boot.

The Armed Citizen® March 27, 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.

Statements to Members Regarding Indemnification

A statement to members regarding indemnification insurance for directors and officers of the National Rifle Association of America.

Review: Colt Enhanced Patrol Rifle II Pro

For many AR-15 enthusiasts, the Colt 6920 remains the benchmark for a solidly built rifle. The company's new Enhanced Patrol Rifle II Pro builds on that legacy with a number of welcome updates.

Winchester Ammunition: More Than Just Ammo

Winchester Ammunition has proven its commitment to the community through several initiatives that show the company is dedicated to making more than just ammunition.

Interests



Get the best of American Rifleman delivered to your inbox.