The .41 Action Express was designed by Evan Whildin, vice president of Action Arms, in 1986. It was based on the .41 Magnum case, cut down to fit in a 9mmP frame, and using a rebated rim. Performance was compared to the ballistics of the 41 Magnum police load. The .41 AE was thought to be a very attractive concept, as the rebated rim allows a simple change of barrel, mainspring, and magazine to convert many 9mm guns to 41 AE.