The 9×23mm Largo (9mm Largo, 9mm Bergmann–Bayard, 9mm Bayard Long) centerfire pistol cartridge was developed in 1903 for the Bergmann–Bayard pistol. It was adopted by the Spanish and Danish militaries, with the former using it until the 1980s, when it was replaced by the 9×19mm Parabellum.

Description and history

thumb|Left to right: 9×23mm Largo, [[9×19mm Parabellum, 9×23mm Winchester, and 9×23mm Steyr]]

The 9mm Largo was developed by Theodor Bergmann and Hugo Schmeisser for the Bergmann–Bayard 1903 pistol. According to Janes, the Spanish military loads had a muzzle velocity of and a muzzle energy of 656 J. While a powerful round, it was used in unlocked breech weapons such as the Astra pistol. Unable to find a German manufacturer to complete the Spanish order for 3,000 pistols, Bergmann turned to a Belgian manufacturer, Anciens Etablissements Pieper (who used the trademark "Bayard"), to complete the order. The final pistol, modified by AEP, was known as the "Bergmann Bayard 1908", or in Spain as the "Pistola Bergmann de 9 mm. modelo 1908". Although adopted in 1908, first deliveries did not take place until the next year. Meanwhile, other manufacturers such as Campo-Giro had adopted the 9mm Bergmann–Bayard round and, due to its long history of use in Spanish submachine guns, carbines and pistols, today it is most commonly known as the "9mm Largo".

In 1910, the Bergmann–Bayard model 1910 semi-automatic pistol was adopted by the Danish military. By 1918, the Bergmann-Bayard was considered obsolete and production was discontinued, though about 1,000 pistols were assembled circa 1918−1920. It has a rimless straight-tapered brass, Berdan-primed case. The bullet is round nosed, lead-cored with a gilded steel jacket. The cartridge has a total weight of . The 9mm Largo and the 9×23mm Steyr have almost identical dimensions, but they can be distinguished by the gilded jacketed bullet on the former, and the Austrian headstamp on the latter.

While external dimensions are almost identical, the 9×23mm Largo is a very different cartridge from the modern, high-performance 9×23mm Winchester. Firing the thicker-walled 9×23mm Winchester round in a 9×23mm Largo pistol is dangerous, as old 9mm Largo pistols cannot handle the pressure generated by the 9×23mm Winchester.

Firearms chambered for 9mm Largo

Anciens Establissements Pieper (AEP)

Destroyer carbine and similar 9mm Largo carbines

  • Ayra Duria et al.
  • Jose Luis Maquibar
  • Onena Carbine
  • Ignacio Zubillaga

Fábrica de Armas, A Coruña

  • Modelo 1941/44 submachine gun (copy of the Vollmer Erma in 9mm Largo) 1941 – mid 1950s
  • Copy of the Bergmann MP28 in 9mm Largo
  • "No maker" Astra 400 (Modelo 1921), 1938–1940s

Fontbernat

  • Labora Fontbernat M-1938 submachine gun

Llama

  • Gabilondo Llama Modelo IV
  • Gabilondo Llama Modelo V
  • Gabilondo Llama Modelo VII
  • Gabilondo Llama Modelo VIII
  • Gabilondo Llama Modelo Extra

Parinco

  • Model 3R submachine gun 1959–?

Republica Española

  • "Naranjero" submachine gun (Modified Bergmann MP28)
  • RE (Republica Española) made Astra 400 (Modelo 1921), 1936–1939
  • Pistol F. Ascaso 1937–1939

Star Bonifacio Echeverria