During the early to mid-1860’s the percussion revolver had to make way for the newly developed self-contained cartridge. During this time the US Army began to look for a new cartridge/revolver combination to replace their rapidly obsolete percussion revolvers. The 44 Colt was developed by Colt around 1871/1872. It was only ever used in the Model 1860 Mason-Richards conversion and was briefly adopted by the U.S. Army but replaced in 1873 by the more powerful 45 Colt. (Erlmeier, Brandt Ref. 403)