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

Kimber 2K11 Pro Comp Review 1
Kimber 2K11 Pro Comp Review 1

Review: Kimber 2K11 Pro Comp

Kimber expanded its 2K11 line with the Pro Comp in 2026, providing a Commander-length slide and barrel topped by an integrated compensator.

New for 2026: Bear Creek Arsenal Bear Bolt Pro

North Carolina-based Bear Creek Arsenal, a prolific maker of AR-10 and AR-15 pattern firearms, is combining the modularity of the MSR platform with a traditional turn-bolt action with its Bear Bolt Pro.

I Have This Old Gun: Model 1854 Lorenz Jägerstutzen

The Austrian Lorenz Jägerstutzen was a unique variant of sharpshooting rifle that made it stateside during the American Civil War.

SHIELD Sights Celebrates 40 Years of Red-Dot Optics Innovation

SHIELD Sights is celebrating its 40th anniversary, marking four decades of British engineering, innovation and contributions to the evolution of modern red-dot optics.

TX Maxed: The Taurus TXM in 5.7x28 mm and .22 WMR

Using its TX series architecture yet again, Taurus is adding the 5.7x28 mm and .22 WMR to its chambering options with the new-for-2026 TXM.

Review: Federal's 6.5 Creedmoor +Peak Ammunition

Federal’s new 6.5 Creedmoor +Peak takes a long-range staple even farther.

Interests



Get the best of American Rifleman delivered to your inbox.