9mm Steyr

9×23mm Steyr
Type	Pistol
Place of origin	Austria-Hungary
Service history
Used by	Austro-Hungarian Army
Production history
Designer	Œ.W.G.
Produced	1911
Specifications
Case type	Rimless, straight
Bullet diameter	9.03 mm (0.356 in)
Neck diameter	9.62 mm (0.379 in)
Base diameter	9.70 mm (0.382 in)
Rim diameter	9.70 mm (0.382 in)
Rim thickness	1.25 mm (0.049 in)
Case length	23.20 mm (0.913 in)
Overall length	32.99 mm (1.299 in)
Primer type	Small pistol
Ballistic performance
Bullet mass/type Velocity Energy 115 gr (7 g) FMJ 1,025 ft/s (312 m/s) 268 ft·lbf (363 J) 115 gr (7 g) FMJ 1,080 ft/s (330 m/s) 298 ft·lbf (404 J) 115 gr (7 g) FMJ 1,230 ft/s (370 m/s) 388 ft·lbf (526 J)
Test barrel length: 128 mm (5.0 in) Source(s): 1. Hornady; 2. Fiocchi; 3. Hirtenberger

The 9mm Steyr is a centerfire pistol cartridge originally developed for the Steyr M1912 military pistol. Adopted in 1912, this was the service ammunition for most branches of the military in Austria-Hungary during World War I and remained the service ammunition for Austria, Romania and Chile between the World Wars. Some MP 34 submachine guns were also issued in this caliber in addition to 9mm Mauser. When the Austrian Army was incorporated in the Wehrmacht in 1938 following the Anschluss, many M1912 pistols and MP 34 submachine guns were rebarrelled to 9×19mm Parabellum for standardization purposes.

It is similar to the 9×23mm Largo cartridge in performance, but their dimensions are just different enough to make them non-interchangeable. The cartridge headspaces on the mouth of the case. Its performance is close to that of the .38 ACP. It is unrelated to the modern 9×23mm Winchester.

Reloadable cartridge cases can be made from 5.56mm NATO, by trimming them to the proper length, but this also requires inside reaming of the case mouths to reduce the thickness of the brass.

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Wikipedia