ProMag Industries Magazine, 223 Remington/556NATO, 30 Rounds, Fits AR Rifles, Roller Follower, Steel Lined Polymer, Black RM-30-SL ProMag magazines are made in the USA and backed by a lifetime guarantee against manufacturer's defects. Magazine springs are precision wound using heat-treated chrome silicon wire and each and every step of the assembly process is checked and double checked in order to maintain the same consistent level of quality.