What cartridge, also known as 9 mm Luger by the C.I.P. or 9 mm NATO by NATO, is used in the submachine gun the MP 40?
9×19mm Parabellum The 9×19mm Parabellum, also known as 9 mm Luger by the C.I.P. or 9 mm NATO by NATO (abbreviated 9mm, 9mmP, 9×19mm or 9×19) is a cartridge that was designed by Georg Luger and introduced in 1902 by the German weapons manufacturer Deutsche Waffen und Munitionsfabriken (DWM) (German Weapons and Munitions Factory) for their Luger semi-automatic pistol.
.38 S&amp;W The .38 S&W (9×20mmR) is a revolver cartridge developed by Smith & Wesson in 1877 for use in the S&W .38 Single Action. Though similar in name, it is not interchangeable with the later .38 Smith & Wesson Special due to a different case shape and slightly larger bullet diameter.