CMMG Inc. has taken 5.7x28mm to a whole new level with the release of the 5.7 AR Conversion Magazine. This innovative new magazine holds 40 rounds of 5.7x28mm and is designed to fit and function in a mil-spec AR15 lower receiver when paired with CMMG’s 5.7x28mm Radial Delayed Blowback upper receiver.
https://www.ammoland.com/2020/01/cm..._6f6fac3eaa-f563b951f6-20556737#axzz6B901yDog
https://www.ammoland.com/2020/01/cm..._6f6fac3eaa-f563b951f6-20556737#axzz6B901yDog