9×21mm

The 9×21mm was designed in Italy and commercialised from 1980 by Israel Military Industries as a commercial-market counterpart to 9×19mm Parabellum: the same bullet at near-identical performance, in a longer case. It exists because several national markets of the period drew a line between service-calibre ammunition and commercial ammunition; ARMAG records no jurisdiction data, and that distinction is named here only because it is the reason the cartridge was designed at all. IMI’s first commercial success with it was the Uzi Defender, a Micro Uzi rechambered for 9×21 IMI and imported into Italy, where the round went on to dominate the commercial pistol market.

The case is a 9×19mm Parabellum case lengthened from 19.05 mm to 21.15 mm, with the bullet seated slightly deeper so that the loaded round’s overall length, 29.75 mm against the 9×19mm’s 29.69 mm, is almost unchanged — close enough that a pistol built for one chambering can often be adapted to the other with a barrel change. Being rimless, it also found a second life in USPSA/IPSC practical shooting’s open class, where a rimless case resists the rim-lock jams that semi-rimmed rounds such as .38 Super can cause in a double-column magazine.

Two loads are recorded here by bullet mass, both drawn from the article’s own C.I.P.-sourced ballistics table.

Gaps on this page: no test barrel length is stated for either load, so no muzzle velocity is recorded — mass only. No ballistic coefficient is published for either load. Neither DVIDS nor Smithsonian Open Access returned a result for this cartridge, consistent with its history as a civilian round outside US military use.