The 9mm Browning Long was a semi-rimmed pistol cartridge introduced alongside the FN Model 1903 blowback pistol. It fell out of favor after World War I and was largely succeeded by the 9×19mm Parabellum.
The 9×20mm Browning Long cartridge was designed by John Moses Browning in 1903 for use in the Model 1903 pistol. It would go on to be adopted by Belgium, France, the Netherlands, and Sweden. The ammunition was produced in Belgium, France, England, Sweden, and the United States. During WWI, it was manufactured in Germany for the Ottoman Empire, which had adopted the M1903 pistol as a standard military service pistol.
The 9×20mm round was a center-fire, semi-rimmed, straight walled pistol cartridge designed by Browning to be manufactured by FN Herstal in Belgium. It was to be almost exclusively marketed to the Europeans.
The original load was a 110 gr (7 g) FMJ bullet going at about 1,000 ft/s (300 m/s) with a muzzle energy output of 240 ft-lbf (330 J). Modern loads are a 108 gr (7 g) FMJ bullet travelling at about 1,150 ft/s (350 m/s) with an output of 316 ft-lbf (428 J).
It is possible to manufacture new 9×20mm cases by cutting down .38 Super brass to the appropriate size.