The present invention relates to systems and methods for reliably limiting the cartridge loading capacity of firearm magazines. In one embodiment, a magazine capacity limiting assembly includes a limiter body and a limiter base. The magazine capacity limiter body reliably operates with a cartridge follower of a firearm magazine. The limiter body is installed substantially within coils of the magazine's spring, thereby limiting the travel of the follower within the magazine body to limit the magazine's cartridge capacity. The limiter base is coupled to both the limiter body and the magazine's floor plate.