Accurate-Mag AICS Pattern Single Stack Magazine 300 Win Mag 5 Round 3.715" Length. This Accurate-Mag magazine is constructed of steel heat treated for maximum durability and carries a black Teflon finish for the greatest longevity. The mag is designed to fit the Accuracy International Chassis System (AICS). This magazine fits the .300 Winchester Magnum round in a single-stack single-feed configuration with a 5 round capacity. Accurate-Mag offers the perfect magazines for any shooter.