I just received an e-mail flyer from Brownells where they advertised some AR magazines at a great price, $9.99 for each 30 rnd mag. I was reading the reviews which for the most part were great. Then one guy said the best magazine is an HK416! Not knowing that much about magazines (mine are all Colt) I looked it up. I am still not much smarter. Which prompted the question. What are good magazines for the AR?