[1] It might have been influenced by the success of the Soviet 9×18mm Makarov, although most observed the opposite (the Ultra cartridge is usually agreed to have been the design basis for the Makarov, with similar case length and a slightly wider and shorter projectile).

It is often interpreted as an intermediate round between 9×17mm and 9×19mm Parabellum, fit for simple blowback pistols.

[2] However, as actually loaded, the cartridge's working pressure and velocities are much closer to those of .380 ACP than to 9×19mm.

[citation needed] The cartridge was made available to the civilian market in 1975,[1] but did not gain lasting popularity.

In addition to the Walther PP Super, the SIG Sauer P230,[1] Mauser HSc-80,[3] and Benelli B76[1] were also produced in 9×18mm Ultra.