Conversion units

[klaus 3338]

Conversion units for the Luger was popular at the beginning of the 20th century. The first came in 4mm M 20. They were used as private, military or Police training units. We can find these in Germany, Switzerland and Sweden. There were mostly patents which protected the different types.
Here is the first one:
Bernhard Müller of Zürich in Switzerland got a patent on his conversion unit in 1911. His unit used a rimfire cartrige in 4mm. Because of it is the rifling not in the middle of the barrel. It was made for the 4 3/4" barrel with cal. 7,65 Parabellum.