9×18mm Ultra
The 9×18mm Ultra is a German pistol cartridge. It is often interpreted as an intermediate round between .380 ACP and 9×19mm Parabellum, fit for simple blowback pistols. However, as actually loaded, the cartridge's working pressure and velocities are much closer to those of.380 ACP than to 9×19mm.
History
The 9x18mm Ultra was originally developed in 1936 for use by the Luftwaffe, but was not adopted at that time.In 1972–1973 Walther introduced the Walther PP Super chambered in 9×18mm Ultra for the West German Federal Police. The choice might have been influenced by the success of the Soviet Makarov pistol, a design heavily based on the original PP and chambered in 9×18mm Makarov, which has similar dimensions to the 9x18mm Ultra, but a slightly wider and shorter projectile; the design of the Makarov cartridge is itself based on the Ultra. However, with the rise in far-left terrorism, it was decided that the new police sidearms should instead be chambered in the more powerful 9×19mm Parabellum, so the 9×18mm Ultra was not adopted.
The cartridge was made available to the civilian market in 1975, but did not gain lasting popularity. The Walther PP Super was discontinued in 1979.
In addition to the Walther PP Super, the SIG Sauer P230, Mauser HSc-80, and Benelli B76 were also produced in 9×18mm Ultra.