Magpul Industries Magazine, PMAG 10 AR4 GEN M3, 223 Rem/556NATO, 10 Round, Fits AR Rifles, Black MAG559-BLK The PMAG 10 AR/M4 GEN M3 is a 10-round 5.56x45 NATO (.223 Remington) polymer magazine for AR15/M4 compatible weapons. Incorporating new material technology and manufacturing processes for enhanced strength" durability" and reliability" the PMAG 10 provides next-generation performance for those needing lower profile magazines. While the GEN M3 is optimized for Colt-spec AR15/M4 platforms" modified internal and external geometry also permits operation with a range of additional weapons such as the HK 416/MR556A1/M27 IAR" British SA-80" FN SCAR MK 16/16S" and others.