9X19 is another name for the standard 9mm it is sometimes called 9mm luger or 9mm parabellum its all the same ammo the 19 refers to the case length

9X19 is another name for the standard 9mm it is sometimes called 9mm luger or 9mm parabellum its all the same ammo the 19 refers to the case length the 9mm NATO is also a 9X19 but is loaded slightly "hotter"

Cleveland, The 9x19mm, also called the 9mm Luger or the 9mm Parabellum, was adopted by the German Army in 1908 as the cartridge for the famous Luger pistol. It has become the world's most popular pistol cartridge. It is now used by most of the militaries of the world, including all of the NATO countries. It is also used by a great many police agencies, including the FBI. The 9x19 is popular with civilians everywhere they are allowed to own handguns in the caliber.