CMMG Guard tuning (9mm) in Pistol Caliber Carbine Posted April 2, 2019 On 3/27/2019 at 3:24 AM, ziebart said: Ferch, I had a lot of issues with the mags falling out and feeding. Eventually CMMG sent me a new mag catch. It might help your issues, but I didn't have any double feeds. I am using 124 Berry's RN at 1.10 COAL and 3.2 gr titegroup. Seems to be working with stock components but we will see. Ziebart- Which weight do you have in the bolt carrier, and what kind of buffer/spring setup are you running?