The L5AWM 300BLK has been specifically engineered for use with subsonic 300 Blackout ammunition, particularly 200+ grain cartridges. The updated internal geometry allows these longer heavier bullets to stack properly, which increases reliability when compared to a traditional .223/5.56 magazine. The outside of the magazine body is molded with 300 Blackout markings and the magazine ships with a contrasting flat dark earth base plate for easy visual identification.