Would anyone care to suggest a brand/model to fit the Mossberg MMR Hunter AR 15? I don't think Mossberg sells "extra" mags like the 5 shot mag that comes with the gun. I'd like to have a second magazine. Heck, I've emailed Customer Relations three times this past week with questions - none have been answered! Not too happy about that. Thanks for any help in identifying magazines that will work, and where to purchase.