The Pistole Parabellum 1908 or Parabellum-Pistole (Pistol Parabellum) — popularly known as the Luger — is a toggle-locked recoil-operated semi-automatic pistol. The design was patented by Georg J. Luger in 1898 and produced by German arms manufacturer Deutsche Waffen- und Munitionsfabriken (DWM) starting in 1900; it was an evolution of the 1893 Hugo Borchardt designed C-93. The first Parabellum pistol was adopted by the Swiss army in May 1900. In German army service it was succeeded and partly replaced by the Walther P38 in caliber 9 x 19.
The Luger is well known from its use by Germans during World War I and World War II, along with the interwar Weimar Republic and the post war East German Volkspolizei. Although the Luger pistol was first introduced in 7.65×21 mm Parabellum, it is notable for being the pistol for which the 9×19 mm Parabellum (also known as the 9 mm Luger) cartridge was developed.
Being one of the first semi-automatic pistols, the Luger was designed to use a toggle-lock action, which uses a jointed arm to lock, as opposed to the slide actions of almost every other semi-automatic pistol. After a round is fired, the barrel and toggle assembly (both locked together at this point) travel rearward due to recoil. After moving roughly 0.5 in (13 mm) rearward, the toggle strikes a cam built into the frame, causing the knee joint to hinge and the toggle and breech assembly to unlock. At this point the barrel impacts the frame and stops its rearward movement, but the toggle assembly continues moving (bending the knee joint) due to momentum, extracting the spent casing from the chamber and ejecting it. The toggle and breech assembly subsequently travel forward under spring tension and the next round from the magazine is loaded into the chamber. The entire sequence occurs in a fraction of a second. This mechanism works well for higher pressure cartridges, but cartridges loaded to a lower pressure can cause the pistol to malfunction because they do not generate enough recoil to work the action fully. This results in either the breech block not clearing the top cartridge of the magazine, or becoming jammed open on the cartridge’s base.
In World War I, as submachine guns were found to be effective in trench warfare, experiments with converting various types of pistols to machine pistols (Reihenfeuerpistolen, literally “row-fire pistols” or “consecutive fire pistols”) were conducted. Among those the Luger pistol (German Army designation Pistole 08) was examined; however, unlike the Mauser C96, which was later manufactured in a selective-fire version (Schnellfeuer) or Reihenfeuerpistolen, the Luger proved to have an excessive rate of fire in full-automatic mode.
The Luger pistol was manufactured to exacting standards and had a long service life. William “Bill” Ruger praised the Luger’s 145° (55° for Americans) grip angle and duplicated it in his .22 LR pistol.
The Swiss Army evaluated the Luger pistol in 7.65×21 mm Parabellum (.30 Luger in North America) and adopted it in 1900 as its standard side arm, designated Ordonnanzpistole 00 or OP00, in 1900. This model uses a 120 mm barrel.
The Luger pistol was accepted by the German Navy in 1904. The Navy model had a 150 mm barrel and a two position (100/200 metre) rear sight. This version is known as Pistole 04.