The magazines are difficult and clumsly to load. I have just learned from Black Dog Machine who make the magazines for the Sig 522 that they now offer a polymer magazine with a pull down button assist. At this time they are available from "Cheaper Than Dirt". Don't know the price. Ciprianski
Michigan Joe, I have a Sig 522 and an HK 416D. I like the balance of the Sig much better than the HK. The Sig's mags are made by Black Dog Machine. They are also the same mags that are used for AR 's that are converted to fire .22 LR. So any mag that is designed for the conversion will fit the Sig 522. Sadly the mags sold with the Sig 522 are almost impossible to load as they do not have what I call an "E-Z Load Button". I added this feature to the two mags I have. I can provide the details if you like. You must have access to a router to make the change. Also, Brownell's (1-800-741-0015) offers a magazine loader for these mags, In catalog # 63, it is part number 100-004-398AD for $14.99.