A magazine for a firearm is formed by a magazine box with a spring therein. A magazine follower in the magazine box is urged toward an open end thereof by the spring, and is formed by a base member extending along a longitudinal axis of the magazine box, and slide stop actuating and cartridge engaging structures extending outwardly from the base member. The slide stop actuating and/or the cartridge engaging structures are resiliently biased in a lateral direction away from a longitudinal axis of the base member to be movable between: (1) a compressed position wherein a longitudinal axis of the slide stop and/or the cartridge engaging structures are laterally perpendicular with the longitudinal axis of the base member, and (2) an uncompressed position where the longitudinal axis of the slide stop actuating and/or the cartridge engaging structures are not laterally perpendicular with the longitudinal axis of the base member.