Abstract: A housing section for a cartridge magazine for a portable firearm, the housing section including: a housing section shell including an inside shell surface, an outside shell surface, and an interior space which forms a first region and a second region; a housing section top side having a first opening cross section; a housing section bottom side having a second opening cross section; a first cross section forming the first region and being configured for accommodating a first number of rows of a plurality of cartridges arranged next to one another; and a second cross section forming the second region and being configured for accommodating a second number of rows of the plurality of cartridges arranged side-by-side, the second number and the first number differing from one another by at least one full numerical value, the first cross section being consistent with the first opening cross section.