What is a rimmed cartridge?

A rimmed cartridge is a type of ammunition characterized by a pronounced rim at the base of the cartridge case, which is wider than the case itself. This design helps to secure the cartridge in the chamber and aids in extraction after firing. Rimmed cartridges are commonly used in revolvers and some rifles, allowing for reliable feeding and extraction. Examples include the .38 Special and .22 Long Rifle cartridges.