The rimmed cartridge is the oldest of the types and has a rim that is significantly larger in diameter than the base of the cartridge. Rimmed cartridges use the rim to hold the cartridge in the chamber of the firearm, with the rim serving to hold the cartridge at the proper depth in the chamber—this function is called "headspacing". Because the rimmed cartridge headspaces on the rim, the case length is of less importance than rimless cartridges. This allows some firearms chambered for similar rimmed cartridges to safely chamber and fire shorter cartridges, such as using .38 Special cartridges in a .357 Magnum revolver. Rimmed cartridges are well suited to certain types of actions, such as revolvers, where the rim helps hold the cartridge in position, and break-open single shot firearms. Rimmed cartridges generally do not work as well in firearms that feed from a box magazine.
Some types of rimmed cartridges, the rimfires, also use the rim to contain the priming compound used to ignite the cartridge.
Examples of rimmed handgun cartridges include the .38 Special, .357 Magnum, .44 Magnum, etc. Rimmed rifle cartridge examples include the .22 Hornet, .303 British, 7.62x54mmR, and more.