9mm Luger Once-Fired Range Brass

The 9×19 mm Parabellum (also known as 9 mm Parabellum or 9 mm Luger) is a rimless, tapered firearms cartridge.

Originally designed by Austrian firearm designer Georg Luger in 1901, it is widely considered the most popular handgun and submachine gun cartridge due to its low cost and extensive availability. It is a standard cartridge for NATO forces as well as in many non-NATO countries.

Since the cartridge was designed for the Luger semi-automatic pistol, it has been given the designation of 9 mm Luger by the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) and the Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (CIP).

A 2007 survey concluded that "about 60 percent of the firearms in use by police are 9 mm [Parabellum]" and credited 9×19 mm Parabellum pistol sales with making semiautomatic pistols more popular than revolvers.

Source: https://en.wikipedia.org/wiki/9%C3%9719mm_Parabellum