Bushmaster has reworked their magazines to offer significant improvements in function, durability and value. The aluminum box is stamped with a full "progressive" die to produce tightest tolerances. The welding process along the box seams has been automated to insure optimum weld ingot, strength and compliance with MIL-STD. The surface finish has been improved to meet or exceed MIL-PRF-46010 (required for U.S.G.I. magazines). Magazine boxes are treated with Molybdenum Disulphide ("Moly") for its exceptional adherence properties which ensure long lasting protection and lubricity - far superior to the PTFE (Teflon) used on other magazines. Finally, these magazines now have a new "anti-tilt" follower that ensures the round is fed into the chamber properly - preventing failure to feed problems. Drop tests have proven the advantages of the anti-tilt follower over the traditional green follower. As an additional aid, the followers are caliber marked - 5.56 in this case. Highest quality tempered steel springs, and Bushmaster logo stamped baseplates (removable for cleaning) round out the improvements on these superior magazines - which have been endorsed by the National Tactical Officers Association.