According to Dixon, there is considerable debate over the origins and purposes of both this and the rimmed equivalent (A42). The RWS ‘10.75×52 G’ and the Austrian ‘10.75×52 Mannlicher’ appear to be the same cartridge. Both have a 12.5-12.6mm head which is used by both the “G” (rimless equivalent of the Gründig rimmed case type) and rimless cases based on the 8mm Mannlicher. An RWS factory drawing dated 19.9.1928 shows this case and confirms its relationship to the Mannlicher type. This is likely to be redrawn from an earlier drawing as RWS did much of this in the 1920’s. Examples exist with “H/19/K&C/02/” , “R.W.S. NüRNBERG” headstamp. There are reports by Rosenberger that there is also a “GR / * / * / * /, but it has not been confirmed as no Roth or Hirtenberger case number is known for this case . Both FMJ and HP bullet types exist.
Interestingly, Rosenberger states when discussing the 9.3×63 and this rimless case type in general, that: “Since the 10.75×50, 10.75×52 and 10.75×60 were announced in the 1902 ammunition catalog of Keller & Co. of Vienna, Austria, but not in others, one must guess that this cartridge family is of Austrian origin.” It appears that he was referring to rimless case types and if so, the 10.75×50 and 10.75×60 are a mystery and not known to exist ?? So, if all of this is correct, then not only is this the rarer rimless version of the 10.75x52R (A42), which it preceedes (being produced by 1902) but also it is a shorter cased version of the 10.75×63 (M57) which also didn’t appear to c1908-1910. (Dixon)