he .450/400 3" was introduced by Jeffery in about 1896 and is a shortened version of the .450/400 Magnum, it was designed as a smokeless round using Cordite and has never been loaded as a black powder cartridge. Before the advent of the .375 H&H; Magnum it was considered to be one of the most versatile all round cartridges of its time. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.