9×21mm (left) and parent 9x19mm Parabellum (right) cartridges
|Place of origin||Israel|
|Designer||Israel Military Industries|
|Parent case||9×19mm Parabellum|
|Case type||Rimless, straight|
|Bullet diameter||9.03 mm (0.356 in)|
|Neck diameter||9.63 mm (0.379 in)|
|Base diameter||9.93 mm (0.391 in)|
|Rim diameter||9.96 mm (0.392 in)|
|Rim thickness||1.27 mm (0.050 in)|
|Case length||21.15 mm (0.833 in)|
|Overall length||29.75 mm (1.171 in)|
|Case capacity||1.01 cm3 (15.6 gr H2O)|
|Rifling twist||254 mm (1 in 10 in)|
|Primer type||Small pistol|
|Maximum pressure||235.00 MPa (34,084 psi)|
The 9×21mm pistol cartridge (also known as the 9×21mm IMI or 9 mm IMI) was designed by Israel Military Industries for those markets where military service cartridges, like the 9×19mm Parabellum, are banned by law for civilian use, like in Italy.
Based on the 9×19mm Parabellum cartridge, the casing was lengthened from 19.05 to 21.15 mm (0.750 to 0.833 in). The bullet sits slightly deeper in the casing, which results in almost the same overall length as the 9×19mm Parabellum cartridge (29.69 to 29.75 mm (1.169 to 1.171 in)).
As it is a rimless round, the 9×21mm is used in USPSA/IPSC competition in Open class firearms. The reasoning is that the rimless case will not lock together with other rounds in a double-column magazine, causing a malfunction. Whereas rimmed cases can sometimes lock together in the magazine, causing a jam. As other .38 Super–based .38 Super Auto rimless cases became available, the 9×21mm decreased in popularity in the United States for competition use, but it is still widely used in the rest of the world.
- 9×21mm IMI
- 9 mm IMI
9×21mm maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm).
According to the official C.I.P. (Commission Internationale Permanente pour l'épreuve des armes à feu portatives) guidelines, the 9×21mm case can handle up to 235 MPa (34,100 psi) piezo pressure. In C.I.P. regulated countries every pistol cartridge combo has to be proofed at 130% of this maximum C.I.P. pressure to certify for sale to consumers.
- "C.I.P. decisions, texts and tables - free current C.I.P. CD-ROM version download (ZIP and RAR format)". Archived from the original on 29 September 2008. Retrieved 2008-10-17.