The .41 Action Express is a pistol cartridge developed in 1986 to reproduce the performance of the .41 Magnum police load (which is a weaker-than-standard load) in semi-automatic pistols.
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.
The powerful 10mm Auto cartridge, which had been suffering from poor acceptance from its start in the early 1980s, was eventually accepted by the FBI in a reduced power, subsonic loading. Smith & Wesson then decided the 10mm Auto was too much cartridge for the reduced power loading, and that the .45 ACP sized guns that chambered it were too heavy and bulky; out of this came the .40 S&W, a shortened 10mm Auto case, designed to fit in a 9mm-sized gun, with a reduced pressure loading that allowed a lighter, easier to shoot gun. Because most ammunition manufacturers backed the .40 S&W, there was little use for the very similar .41 AE, so production of both firearms and ammunition was soon phased out.
The .41 AE was doomed by circumstance to obscurity, but the concept of using a rebated rim to allow easy cartridge interchangeability was not lost. The .50 Action Express, developed by Magnum Research for the Desert Eagle pistol, uses a similar rebated rim that is the same diameter as the .44 Magnum. This allows a caliber change with replacement of just the barrel and magazine.
The .41 AE can be ballistically similar to the .40 S&W, to the point that many reloading manuals suggest using .40 S&W load data in the .41 AE. Original IMI factory cartridges are much higher powered, pushing a 170 gr (11.02 g) bullet at 1215 ft/s. The .41 AE uses 0.410-inch (10.4 mm) bullets, whereas the .40 S&W uses 0.400-inch (10.2 mm) bullets. However, as it lacks the backing of ammunition manufacturers in making .410 caliber bullets suited to semiautomatic pistols, the .41 AE has not achieved widespread popularity.
There have been several firearms chambered for this cartridge, most notably the Israeli Uzi and the Jericho 941. The potential for success for the 41 AE was sound, and for this reason, other manufacturers offered firearms chambered at the factory for this round. Additionally, aftermarket conversion kits were available as well.Uzi Carbines and pistols
Desert Eagle early models could cross-caliber between .41AE, .357 Magnum, .44 Magnum and later .50 AE
Baby Eagle (the later name for the Magnum Research imported Jericho pistol)
In 1988, IMI also developed a 9 mm Action Express, which was a .41 AE necked down to 9 mm. It offered a much larger case capacity than the standard 9 mm case, allowing velocities that matched that of the .357 Magnum when loaded with light bullets. This move anticipated the parallel development of the .357 SIG from the .40 S&W in 1994.