I have a DPMS Mk 12 and have been happy with it. Thought it was a little heavy at first but wife has a RRA Elite Operator 223 and the Mk 12 is very close in weight. It shoots anything I put in it and the only malfunctions are caused when I use a brass catcher and the brass doesn't completely clear the ejection port due to the bag. It likes the 150 Hornady reloads I use and once I dialed in my SWFA it shot this 5 shot group (Bottom 5 were zeroing scope) at 100 yds. I recently added an Atlas bipod and a BCM CH. The trigger is scary light unlike the RRA heavier two stage trigger pull on wife's gun. I use the DPMS and Magpul P mags in it with no problems.