June 23, 2014 An overview and range demo of the CMMG Mk4 RCE rifle, available in 5.56 NATO and 300BLK. Share this gun video:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Tumblr (Opens in new window)