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