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.
![Ruger 250Th[16]](/media/ss1dj10i/ruger-250th-16.jpg?anchor=center&mode=crop&width=770&height=430&rnd=134202089811930000&quality=60)
![Ruger 250Th[16]](/media/ss1dj10i/ruger-250th-16.jpg?anchor=center&mode=crop&width=150&height=150&rnd=134202089811930000&quality=60)
