The 9 mm Parabellum, most commonly referred to the Handgun, e.g. what 9mm do you have? this is very widely used and should be correctly named and referred to the Firearm manufacturer and the calibre of what that firearms fires.
Abbreviated 9 mm, 9 mmP, 9×19 mm or 9×19, cartridge was designed by Georg Luger and introduced in 1902 by the German weapons manufacturer Deutsche Waffen- und Munitionsfabriken (DWM) for their Luger semi-automatic pistol. For this reason, it is designated as the 9 mm Luger / 9 mm Luger +P by the SAAMI, and the 9 mm Luger by the C.I.P. (differentiating it from the 9 mm Makarov and 9 mm Browning cartridges). Under STANAG 4090, it is a standard cartridge for NATO forces as well as many non-NATO countries.
The name Parabellum is derived from the Latin words, Si vis pacem, para bellum (“If you seek peace, prepare for war”), which was the motto of DWM.
According to the 2006 edition of Cartridges of the World, the 9×19 mm Parabellum is “the world’s most popular and widely used military handgun cartridge.” In addition to being used by over 60% of police in the U.S., Newsweek credits 9×19 mm Parabellum pistol sales with making semiautomatic pistols more popular than revolvers. The popularity of this cartridge can be attributed to the widely held conviction that it is effective in police and self-defense use. Its low cost and wide availability contribute to the caliber’s continuing popularity.
Georg Luger developed the 9×19 mm Parabellum cartridge from his earlier 7.65×21 mm Parabellum round, which itself was derived from the original 7.65×25 mm Borchardt cartridge in the Borchardt C-93 pistol. Shortening the length of the cartridge case used in the Borchardt pistol allowed him to improve the design of the toggle lock and to incorporate a smaller, angled grip.
Luger’s work on the Borchardt design evolved into the Luger pistol, first patented in 1898 and chambered in 7.65×21 mm Parabellum. Demand for larger calibers in military sidearm’s led to Luger to develop the 9×19 mm Parabellum cartridge for his new pistol. This was achieved by removing the bottleneck shape of the 7.65×21 mm Parabellum case, resulting in a tapered rimless cartridge encasing a bullet that was 9 mm in diameter.
In 1902, Luger presented the new round to the British Small Arms Committee, as well as three prototype versions to the U.S. Army for testing at Springfield Arsenal in mid-1903. The Imperial German Navy adopted the cartridge in 1904 and in 1908 the German Army adopted it as well. The ogive of the bullet was slightly redesigned in the 1910s to improve feeding.
To conserve lead during World War II in Germany, the lead core was replaced by an iron core encased with lead. This bullet, identified by a black bullet jacket, was designated as the 08 mE (mit Eisenkern—”with iron core”). By 1944, the black jacket of the 08 mE bullet was dropped and these bullets were produced with normal copper-colored jackets. Another wartime variation was designated the 08 sE bullet and identified by its dark gray jacket, and was created by compressing iron powder at high temperature into a solid material (Sintereisen—”sintered iron”).
After World War I, acceptance of the 9×19 mm Parabellum chambering increased, and 9×19 mm Parabellum pistols and submachine guns were adopted by military and police users in many countries. The 9×19 mm Parabellum has become the most popular caliber for U.S. law enforcement agencies, primarily due to the availability of compact pistols with large magazine capacities that use the cartridge.
Worldwide, the 9×19 mm Parabellum is one of the more popular pistol cartridges where it is legal, some countries ban civilian use of weapons that chamber current or former military service cartridges, and cartridges in this caliber are generally available anywhere pistol ammunition is sold.
From the early 1980s to the mid-1990s, a sharp increase occurred in the popularity of semiautomatic pistols in the U.S., a trend foreshadowed by the adoption of the Smith & Wesson Model 39 by the Illinois State Police in 1968. In addition, the Beretta M9 (a military version of the Beretta Model 92) was adopted by the U.S. Army in 1985. Previously, most American police departments issued .38 Special caliber revolvers with a six-shot capacity.
The .38 Special was preferred to other weapons such as variants of the M1911 because it offered low recoil, was small and light enough to accommodate different shooters, and was relatively inexpensive. The 9 mm is ballistically superior to the .38 Special revolver cartridges, it is shorter overall, and being an autoloader cartridge, it is stored in flat magazines, as opposed to cylindrical speed loaders. This coupled with the advent of the so-called “wonder nines” led to many U.S. police departments exchanging their revolvers for some form of 9 mm semiautomatic handguns by the 1980s.
In 2014, the FBI released a report detailing the potential combat effectiveness of the 9 mm cartridge when compared to other calibers such as the .45 ACP and the .40 Smith & Wesson cartridge that was specifically developed for use by the FBI. The report indicated that the new powders and more advanced bullet designs used in current 9 mm defensive loads allowed for the caliber to deliver comparable performance to other calibers, like the .45 ACP, and .40 S&W.
In addition to this, the lower recoil, less wear, and higher capacity were all reasons that the report cited for the recent surge in orders of the ammunition from various police agencies. With a wider selection of officers being able to shoot handguns chambered in 9×19 mm, many departments choose this caliber so they can standardize around a single firearm and loading, making logistics and supply easier. Due to all of these factors, law enforcement orders of 9mm ammo from all major ammunition manufacturers have spiked dramatically.
Some of the information on this page was sourced from Wikipedia