Maybe the following clarifies the matter:
Ernst August vom Hofe (died 1945) was a German weapons and ammunition designer known for developing high-velocity hunting cartridges. Together with Richard Schienmann, he founded the company HOFMANN WAFFEN und MUNITION, which operated under the name VOM HOFE WAFFEN und MUNITION from 1935 onwards.
The 7x73 Super Express vom Hofe was developed in 1931 by Ernst August vom Hofe and his partner Schienmann for Mauser 98 systems. The corresponding weapons were produced by the Hoffmann company in Berlin. After 1936, vom Hofe also produced weapons in this caliber under his own name. The use of a belt on the case was unusual for a German manufacturer. In 1937, the two 5.6x61 Super Express vom Hofe cartridges were developed, for which there is a rimmed version and also a rimless version. the 7x66 SE vom Hofe was designed in 1955 by Walter Gehmann. His goal was to achieve the case volume of the 7x73 Super Express vom Hofe from 1931 with a case length of 66 mm, thus allowing it to be used in standard Mauser systems. Unlike the 7x73 Super Express vom Hofe, the 7x66 SE vom Hofe does not have a belted case.
The 7 × 66 mm Suoer Express vom Hofe was developed in 1955 by Walter Gehmann as a further development of the 7 × 73 mm vom Hofe, which in turn was based on the .300 Holland&Holland. The 7 × 66 mm SE vH has the same case volume as its predecessor, the 7 × 73 mm vom Hofe, but is 7 mm shorter. This means it also fits into standard systems. The cartridge was originally developed for post-war Vom-Hofe weapons, which in turn were based on the Swedish Husqvarna-Mauser system (“Schwedenmauser”). It was launched in Germany in 1956 and in the USA in 1962. Later, the caliber was also used in other systems, such as the Mauser 66. The 7x75R Super Express vom Hofe was developed in 1958 for break-action rifles based on the 9.3x74R case.
The 5,6x61 Super Express vom Hofe as a rimless as well as rimmed version which were developed in 1937 are still sometimes used in Germany and Austria beside the two "Gehmann developments" that carry the name "vom Hofe" as a high-velocity round. In any case these are very interesting historic rounds.
