Colt Mfg SP62103RP USGI 20rd 5.56x45mm NATO Blued Aluminum
http://www.tandktactical.com/shop/098289900357-colt-mfg-sp62103rp-usgi-20rd-5-56x45mm-nato-blued-aluminum-18519
http://www.tandktactical.com/web/image/product.template/18519/image_1920?unique=4aee9de
This magazine is compatible with Colt USGI MSR.