Elmer Keith's No.5 Single Action Army is arguably the most famous custom revolver ever made. Keith had it built in 1928 after developing a friendship with Harold Croft, another revolver enthusiast. Croft had shown Keith his own custom revolvers, which he had numbered 1 through 4. Croft had been trying to make an ideal pocket gun, and Keith used several of his ideas along with some of Keith's own to put together a revolver for general-purpose field use. In recognition of Croft's work, Keith called his gun Number 5. It featured an extended flat top with windage-adjustable sights, an improved mainspring, redesigned cylinder pin, custom hammer spur, and modified Bisley grip. It was chambered for the .44 Special/.44 Russian cartridges (the Russian being a slightly shorter version of the Special), and it was Keith's favorite shooting piece until the .44 Magnum cartridge was introduced in the late 1950s. He described this gun in detail in a 1929 American Rifleman article entitled "The Last Word".