The MP-34 was made by Steyr-Solothurn in four different calibers - 9x19 for the Germany army, 9x25 for the Austrian army, 9x23 for the Austrian police, and .45 ACP for the export market. This is one of the .45 caliber examples, of which only about 500 were made, all for South American countries (including El Salvador, Chile, Bolivia, and Uruguay). The gun shares most of its parts with the 9mm versions, with the exception of the magazine housing, rear sight mounting, bolt, and barrel. The receiver and magazine housing are the same length as the standard pattern, which much simplified production; it just has a wider housing to fit the double-stack 20-round .45 caliber magazine. In addition, because of the lack of common .45 ACP stripper clips, the clip-loading feature of the MP-34 mag housing was left off the .45 caliber model.