9mm Examples

9x18 Ultra (9mm Police): Developed in 1936 as a possible service cartridge for the German Luftwaffe, it’s slightly more powerful than the .380 ACP, but still suitable for blowback pistols. With war imminent, the project was shelved. Around 1972 Walther revived it for use in the West German Police PP Super until it was discontinued in 1979. SIG, Mauser and Benelli also made some blowback pistols for 9x18 Ultra.

9x18 Makarov (9mm Makarov, 9mm Mak, 9x18 PM, 9x18 Soviet): Unlike almost all other nines, which use bullets of 0.355" to 0.356" diameter, the 9mm Mak uses 0.365" bullets. It’s widely used in Soviet bloc nations as a handgun and submachine gun cartridge.

9x20 SR (9mm Browning Long): Developed in 1903 along with the FN 1903 pistol. Like the Colt series, it’s semi-rimmed, hence the SR designation. It’s less powerful than the 9x19, since it was a blowback design unlike the locked-breech Luger. Sweden adopted the FN as their military sidearm in 1907. When supply was cut during WWI Husqvarna manufactured under license. Made to high standards, they became available as surplus in the U.S. in the 1960s. Many were converted via a chamber sleeve to accept .380 ACP ammunition.