CMMG Mk57 Upper ConversionThe CMMG Mk57: A 5.7 upper that works CMMG continues on the 5.7×28 revival path.  Last year, we reviewed CMMG’s FiveSeven magazine compatible 5.7×28 Banshee.  Further reinforcing the 5.7×28 revival is CMMG’s new Mk57 Upper Conversion kit for standard AR lowers.  Of most import is the fact that CMMG developed a 40 round 5.7×28 magazine […]

Read More …

The post TFB Review: CMMG Mk57 5.7x28mm Conversion Kit appeared first on The Firearm Blog.

https://www.thefirearmblog.com/blog/2020/03/19/tfb-review-cmmg-mk57-5-7x28mm-conversion-kit/?utm_source=rss&utm_medium=rss&utm_campaign=rss&utm_source=rss&utm_medium=rss&utm_campaign=tfb-review-cmmg-mk57-5-7x28mm-conversion-kit