The 9×19 mm Parabellum, also known as the 9 mm Luger by C.I.P. or 9 mm NATO by NATO, is a pistol cartridge introduced in 1902 by the German weapons manufacturer Deutsche Waffen und Munitionsfabriken (DWM) for their Luger pistol. Its parent cartridge was the 7.65x22mm Parabellum, itself a descendant of the earlier 7.65x25mm Borchardt cartridge. The 9×19 mm Parabellum is commonly used in pistols, submachine guns and carbines.
The name Parabellum is derived from the Latin: Si vis pacem, para bellum ("If you seek peace, prepare for war"), which was the motto and telegraphic address of DWM.
Georg Luger developed the 9×19 mm Parabellum cartridge from the earlier 7.65 mm Parabellum pistol cartridge. 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 German military expressed official interest in a 9 mm version of the Parabellum in 1904.
The initial cartridge was created by removing the bottleneck of the 7.65 mm Luger cartridge, resulting in a tapered rimless cartridge. The ogive of the bullet was slightly redesigned in the 1910s in order to improve feeding.
After World War I, acceptance of this caliber increased and 9 mm pistols were adopted by a number of countries.
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").
A special load (identified either by an "X" on the headstamp or by a green lacquered steel case) with a 9.7-gram (150 gr) full metal jacket bullet with a subsonic muzzle velocity for use with suppressed firearms was produced by the Germans during WWII. Other countries also developed subsonic loads.
Many police departments that use 9 mm rounds in their handguns switched to 8-gram (120 gr) bullets after the investigation of the 1986 FBI Miami shootout, because the lighter 7.4-gram (114 gr) loading used by the officers in that incident was found to be less effective than a heavier load like the 8.0 g. Bullets weighing up to 9.5 grams (147 gr) are available.
The 9 mm cartridge has been manufactured by, or for, more than 70 different countries and has become a standard pistol caliber for NATO and other military forces around the world. Its official nomenclature among NATO users is "9 mm NATO". The 9 mm NATO can be considered as an overpressure variant of the 9×19 mm Parabellum, that is defined by NATO standards. The service pressure Pmax of the 9 mm NATO is rated at 252 MPa (36,550 psi) where C.I.P. rates the 9 mm Luger PTmax somewhat lower at 235 MPa (34,083 psi). The 315.0 MPa (45,687 psi) proofing test pressure used in the 9 mm NATO proof test however equals the proofing test pressure used in the 9 mm Luger C.I.P. proof test.
The Russian military adopted specialized 9×19 mm high velocity cartridges with relatively light bullets for both pistols and submachine guns to defeat body armour. Besides enhanced penetration capabilities these overpressure variants offer a flatter trajectory and lessened recoil. After initial research, conducted since the late 1980s under the codename "Grach", the Russian armed forces adopted two specialized 9×19 mm variants.
The 7N21 9x19 mm overpressure variant MPa features an armour piercing bullet and generates a claimed peak pressure of 280 MPa (40,611 psi). The 7N21 bullet features a hardened (sub-caliber) steel penetrator core, enclosed into a bimetal jacket. The space between the core and jacked is filled with polyethylene, and the tip of the penetrator is exposed at the front of the bullet, to achieve better penetration. The MP-443 Grach and GSh-18 pistols and PP-19-01, PP90M1 and PP-2000 submachine guns were designed for usage with this overpressure cartridge.
In the 7N31 9×19 mm overpressure variant the same concept with a similar but lighter bullet that achieves higher muzzle velocity is applied. The 7N31 cartridge was developed in the late 1990s for the GSh-18 pistol. The 7N31 was also adopted for the PP-2000 submachine gun. Its maximum service pressure remains unclear
During the period between the early 1980s and the mid-1990s, a sharp increase in the popularity of "Wonder Nines" coincided with the adoption of the Beretta M9 by the US Army. At the time, most police departments were issuing .38 Special caliber revolvers with a six-shot capacity. The .38 Special was advantageous to other options like variants of the M1911 because it offered low recoil, the revolvers were small and light enough to accommodate different shooters, and it was relatively inexpensive. Possessing superior ballistics to the .38 Special revolver cartridge, the 9 mm is a shorter round, and being an autoloader cartridge is stored in flat magazines as opposed to cylindrical speedloaders or moon clips used with revolvers, ammunition carrying capacities could be easily increased by as much as 250%. The 9 mm pistol cartridge can be accommodated in a compact frame pistol, able to be used more effectively by inexperienced shooters and smaller-framed officers.
Attempts to improve ballistics of the cartridge came in the early 1990s with the widespread availability of high pressure loadings of the 9 mm cartridge. Such overpressure cartridges are labeled "+P" or in the case of very high pressure loadings "+P+". Ballistic performance of these rounds was moderately improved over the standard loadings. In addition, improvements in jacketed hollow point bullet technology have produced bullet designs that are more likely to expand and less likely to fragment than earlier iterations, giving a 9 mm bullet greater damage capability while retaining its compact cartridge size.
The .40 S&W round debuted at the 1990 S.H.O.T. show. The .40 S&W sought to fill the gap between 9 mm and .45 ACP. While increasing bullet diameter by roughly half the difference between 9 mm and .45 ACP, the .40 S&W retained the same SAAMI standard pressure load limits of the 9 mm (240 MPa, 35,000 PSI). This afforded only a 20% (typical) capacity loss when compared to the 9 mm.
The 9 mm cartridge combines a relatively flat trajectory with moderate recoil. The main advantage lies in its being among the smallest of the "large caliber" rounds, allowing users to carry greater capacity compared to larger rounds like .40 S&W and .45 ACP. Combined with the lower felt recoil as compared to a larger round, 9×19 mm Parabellum-chambered handguns allow the shooter to place more shots accurately and more quickly than a handgun chambered for a larger cartridge — this is compared to calibers such as .22, where minimal recoil is more than offset by minimal effectiveness against human targets. The "Wonder Nine" design theory, resulting in handguns like the Glock 19, is the result of attempts to maximize these advantages by more than doubling magazine capacity over comparably-sized pistols in larger calibers like the M1911.
The energy delivered by most 9 mm loads allows for adequate expansion and penetration with premium JHP bullets. Illinois State Police, Border Patrol, Federal Air Marshals and United States Secret Service favored and used 115 grain +P+ 9 mm loads at 1,300 fps for years with excellent results. Lethal Force expert Massad Ayoob has stated that the "Tried, Tested, and True" 115 grain +P or +P+ is the best self defense load in this caliber. This was also part of the reason why Secret Service and Air Marshals chose the 125 grain .357 Sig at 1,350 fps to replace the 9 mm for a duty round. The energy may be marginal for imparting hydrostatic shock in human-sized living targets, though the existence of this phenomenon has been questioned, especially regarding its possibility with handgun cartridges.