An increased capacity replacement firearm ammunition
magazine for a
polymer or
polymer-over-
metal single stack firearm ammunition
magazine for a GlockĀ® handgun, comprises a metallic body dimensioned to compatibly replace the single stack
magazine for the GlockĀ® handgun, the single stack magazine having a body having exterior dimensions defined by
polymer or polymer-over-
metal forward, aft, and side walls, the metallic body having exterior dimensions defined by metallic forward, aft, and side walls, an exterior width dimension of the metallic side walls compatibly matching an exterior width dimension of the side walls of the single stack magazine body, the metallic walls being thinner than the walls of the single stack magazine, the thinner metallic walls allowing an at least partially laterally offset arrangement of cartridges in the metallic body, the forward wall of the metallic body including at least one spacer extending along the forward wall, the spacer sized such that a forward-to-aft
exterior dimension of the metallic body compatibly matches a forward-to-aft
exterior dimension of the single stack magazine body, a length dimension of the metallic body compatibly matches a length dimension of the single stack magazine body, a
cut-out in the metallic body adapted to receive a firearm magazine catch therein, the
cut-out including an upper edge, and polymer over at least the upper edge of the
cut-out.