After the introduction if the 44 Magnum in 2956, few companies as well as shooters (except Elmer Keith and Skeeter Skelton) recognised the need for a .40 cal cartridge that could operate between the Elmer Keith brainchilds, namely the 357 Magnum and the 44 Magnum. Keith convinced Remington and Smith & Wesson to develop the 41 Magnum, but at roughly the same time Colt engineer Bob Roy developed a .40 cal. cartridge that was made by cutting down 30-30 Win cases and loading them with a .40 cal. bullet. They contracted Winchester to produce the cases for them and loaded them with a 200 gr.GM flat tip lead bullet. In this case, Remington got the drop on the fols at Colt and launced the 41 Magnum ahead of the Winchester version, effectively ending the whole project. It did not enter commercial production and only a few test lots were manufactured. Except for the smaller rim diameter, the 400 Colt Magnum is the same as the 41 Rem Mag. (Erlmeier, Brandt Ref. 381)