Accurate-Mag AICS Pattern Single Stack Magazine, 338 Lapua Mag 5 Round, 3.850" Length. This Accurate-Mag magazine is made from a strong steel, heat treated for the best durability, and carries a black Teflon finish for increased mag longevity. The magazine is designed to fit the Accuracy International Chassis System (AICS). This magazine fits the .338 Lapua Magnum round in a single-stack single-feed configuration with a 5 round capacity.