A Legendary caliber deserves a legendary magazine and the 400 Legend Duramag SS delivers the only purpose built magazine for this caliber. With these Duramag SS mags you’re getting 400 Legend specific rib geometry which is crucial to reliable feeding and cartridge stack internally. These magazines are also marked with 400 Legend on the body and the follower to help with quick identification. - The 400 Legend DURAMAG SS is an AR-15 pattern magazine designed for serious shooters who require the most out of their magazines. Constructed from premium 410 Stainless Steel and built with advanced interior and exterior geometries to ensure ultimate reliability and feeding. These magazines utilize our T-360 coating to ensure incredible performance and product longevity through the harshest conditions. The 400 Legend magazines are available in 5rd and 10rd capacities and safe for extended storage while loaded. DURAMAG will not flex or swell like polymer due to storing while loaded or environmental / temperature changes. When performance and durability are paramount make the switch to DURAMAG SS and never look back.