The Steyr M1912, or Steyr Hahn (meaning “hammer”, to distinguish it from the striker-fired Steyr 1907) has a number of features that make it unusual among pistols today. It uses a fixed internal magazine fed via stripper clips, and a short recoil, rotating barrel locking system. Only a handful of other pistols have been made with rotating barrel systems, like the Steyr 1907, Beretta PX4, Savage 1907/1915, Mexican Obregon, GSh-18, Colt All-American 2000, MAB P-15, Boberg, and CZ-24. Rotating barrel pistols are often touted as being more accurate than others (generally the comparison is made against Browning-type tilting barrel designs), but this appears to be entirely theoretical. Any true advantage is small enough to be overridden by other factors.
Between 1912 and 1919 about 300,000 of these pistols were made for the Austrian military, which used them alongside Rast & Gasser M1898 revolvers. The 9mm Steyr cartridge they fire is roughly equivalent to 9mm Parabellum, despite having a longer case. Some 60,000 of the pistols were later converted to 9×19 after the Anschluss and used by the German military in WWII.