The .450/400 Nitro Express are a family of .405 - .411 caliber, rimmed, bottlenecked cases which was originally intended for black powder single shot and double rifles. There were multiple variants of each cartridge as variations existed between each manufacturer for each cartridge length. The lengths of the cartridges ranged from 3¼ inches to 2⅜ inches (82.55 mm - 60.33 mm) in case length.