The 9×21mm
pistol cartridge (also known as the 9×21mm GP, 9×21mm IMI, 9mm IMI, 9×21mm Italian, or 9mm Italian) was designed by Jager (Loano, Italy), then adopted and commercialised by
Israel Military Industries for those jurisdictions where military service cartridges, like the
9×19mm Parabellum
The 9×19mm Parabellum (also known as 9mm Luger, 9mm NATO or simply 9mm) is a Rim (firearms)#Rimless, rimless, Centerfire ammunition, centerfire, tapered cartridge (firearms), firearms cartridge.
Originally designed by Austrian firearm designer ...
, are or were illegal for civilian purchase (i.e. Italy, France, Brazil, and Mexico).
History
Based on the 9×19mm Parabellum cartridge, the case was lengthened from . The bullet sits slightly deeper in the case, which results in almost the same overall length as the 9×19mm Parabellum cartridge ().
The cartridge was designed by Erasmus Giordano & Armando 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 1980s,
Israel Military Industries (IMI) started to use 9×21mm and received permission to import the UZI Defender (also called
Micro Uzi) into Italy chambered for 9×21 IMI. It was the first official commercial launch for the 9×21mm. From that period on several companies in Italy started to sell 9×21mm pistols and ammunition. In just a few decades, the 9×21mm GP or 9×21 IMI became roughly 80% of the civilian small arms market in Italy.
Competition use
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 semi-rimmed or rimmed cartridges, it will not tend to lock together with other rounds in a double-column magazine, resulting in a
malfunction
A malfunction is a state in which something functions incorrectly or is obstructed from functioning at all.
Some types of malfunctions are:
*Malfunction (parachuting)
A malfunction is a partial or total failure of a Parachute, parachuting de ...
. 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 many other parts of the world.
Synonyms
*9×21mm IMI
*9 mm IMI
*9mm Italiano
*Winchester 9×21mm WIN
24-gr. bullet
Cartridge dimensions
The 9×21mm has 1.01
ml (15.5
grains
A grain is a small, hard, dry fruit ( caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and le ...
H
2O) cartridge case capacity.
9×21mm maximum C.I.P. cartridge dimensions
All sizes in millimeters (mm).
The common
rifling
Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such groov ...
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 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.
See also
*
9 mm caliber
*
List of handgun cartridges
*
List of cartridges by caliber
References
Further reading
*
{{DEFAULTSORT:9by21mm
Pistol and rifle cartridges
*
Paramilitary cartridges