Using the best materials is of paramount importance that is why Mec-Gar takes into account tensile strength, elongation rate and chemical composition of all raw materials. Before materials are accepted into production they are carefully tested and checked. Made from certified AISI 1010 Carbon Steel. Revised dimpled design accepts standard Mec-Gar floorplates, springs, and follower Carbon steel tube, heat-treated for strength High tensile music wire spring Polymer follower and floorplate