US Patent 7797871 Magazine for a firearm

A magazine for improved stacking capacity includes a housing, a front wall connected to a back wall by sidewalls, a base, a spring adapted to be received inside a recess in the base in order to reduce the space occupied by the spring. The spring having various spiral sections wherein the spiral section having different lengths so that the spiral sections fit into each other when the spring is compressed against cartridges in order to enable stacking of additional cartridges.