ProMag RM10: ProMag\'s Rollermag reinvents the wheel by adding them to an anti-tilt follower, in a Technapolymer magazine body. Experience a smooth, anti-tilt rolling feed with the revolutionary RollerFollower for maximum friction reduction. The magazine is built with ProMag\'s anti-fatigue chrome silicon springs, so you can keep them loaded and stashed for up to six years without worry. This model has a 10-round 223 Rem/5.56 NATO capacity.