9×21mm

9×21mm
9×21mm
	9×21mm (left) and parent 9×19mm Parabellum (right) cartridges
Type	Pistol
Place of origin	Israel
Production history
Designer	Israel Military Industries
Specifications
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)
Ballistic performance
	Source(s): C.I.P.[1]

The 9×21mm pistol cartridge (also known as the 9×21mm IMI or 9 mm IMI or 9x21mm Italian or 9mm Italian) was designed by Jager (Loano, Italy), then adopted and commercialised by Israel Military Industries for those markets where military service cartridges, like the 9×19mm Parabellum, are banned by law for civilian use (such as in Italy).

History

Based on the 9×19mm Parabellum cartridge, the case was lengthened from 19.05 to 21.15 mm (0.750 to 0.833 in). The bullet sits slightly deeper in the case, 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)).

The cartridge was designed by Mr. Giordano & Mr. Piscetta to be used for civil purposes with large pistols (also those designed for .45 ACP). It was named 9 mm GP. The users were not enthusiastic at the very beginning for several reasons, such as the fact that barrels had to be modified.

During the '80's, the cartridge became the perfect caliber to be used for all those automatic pistols designed for military cartridges (i.e.9x19mm) all over the world that are frequently forbidden for civilian uses; for this reason Israel Military Industries (IMI) started to use 9x21mm. During that period IMI got permission to import the UZI Defender (also called Micro Uzi) into Italy chambered for 9x21 IMI. It was the first official commercial launch for the 9x21mm. From that period on several companies in Italy started to sell 9x21mm pistols and ammunition. In just a few decades, the 9x21mm GP or 9x21 IMI became roughly 80% of the civilian small arms market in Italy.

Notes

As it is a rimless round, the 9×21mm is used in USPSA/IPSC competition in Open class firearms. A rimless case is preferred because, unlike rimmed cartridges, it will not tend to lock together with other rounds in a double-column magazine, resulting in a malfunction. As other .38 Super–based rimless cartridges 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.

Synonyms

9×21mm IMI
9 mm IMI
9mm Italiano
Winchester 9×21mm WIN [124-gr. Bullet]

Cartridge dimensions

The 9×21mm has 1.01 ml (15.5 grains H₂O) cartridge case capacity.

9×21mm maximum C.I.P. cartridge dimensions.[1] All sizes in millimeters (mm).

The common rifling twist rate for this cartridge is 254 mm (1 in 10 in), 4 grooves, Ø lands = 8.79 mm, Ø grooves = 9.03 mm, land width = 3.80 mm and the primer type is small pistol.

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.

gollark: It *does* break compatibility if `setfenv` isn't available.

gollark: You can also use `setfenv`, but I think that might go away eventually? Depends on the will of the squidly one.

gollark: `load(your_code, filename [or nil, probably], "t", environment_table)`

gollark: Well, the sandboxing backend for potatOS does, but it's close enough.

gollark: PotatOS just passes in a replacement `_G` table to `load`.

References

"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 June 6, 2009. Retrieved 2008-10-17.