Magpul PMAG 30 AR 300BLK Gen M3 magazine designed for 300 Blackout carbines. GEN M3 features a crush/impact resistant polymer, aggressive texture, easily removable slim floor plate, and a paint pen dot matrix for marking. Specifically designed for 300 BLK performance and reliability; cross-loading issues can occur when using 5.56 magazines in 300 BLK rifles.