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.
.38-40 Winchester The .38-40 Winchester is actually a .40 caliber cartridge shooting .401 caliber bullets. The cartridge was introduced by Winchester in 1874 and is derived from their .44-40 Winchester. This cartridge was introduced for rifles, but in its reintroduction for Cowboy Action Shooting it has seen some popularity as a pistol cartridge. It is not particularly well suited to hunting larger game, but it was popular when it was introduced, along with the previous .44-40 Winchester, for deer hunting. It can be used successfully on smaller game animals, and for self-defense. Current loadings are intended for revolvers.