heavymetal, 9mm steyr is one of the many varieties of 9mm. 9 mm luger (most common) is also known as the 9x19; then there is 9x18 Russian; 9x21 developed in Europe because civees are forbidden from having 9x19 which is for military/LEO use only; 9x23 was recently developed here in US by winchester if I remember correctly; 9mm largo etc. Nix,
This has been batted around some before. See this thread: 9mm Steyr, .38 Auto and 9x23mm And this thread: So here's an odd one... 9x21mm M(A1)? And this article about the Bergmann Bayard M1910/21 pistol is quite informative on it also.