The 41 Action Express was developed at the end of 1986 or early 1987 by Evan Whilden who designed the cartridge and Bob Olsen from Olsen Development Labs who did the designs on the gun. With the 41 Magnum not being the success that S&W hoped for, Evan and Bob set out to duplicate 41 Magnum ballistics by having a 200gr. bullet at 1,000 fps but in a pistol as opposed to a revolver and utilising the same case head as the 9mm Parabellum. .Certain law enforcement agencies like the FBI adopted the 10mm Auto in the early 1980’s in a reduced powered sub-sonic loading, but S&W ultimately decided that the 10mm was too heavy for such a reduced loading and they also did not want to go back to the heavy, cumbersome 45 ACP’s available at the time, so they shortened the 10mm Auto case and came up with the 40 S&W which was balistically the same as the 41 AE. This was probably the biggest reason for the 41 AE not being successful. (Erlmeier, Brandt Ref. 384A)