Sometimes I shoot my CZ 52 pistol in matches. There have been up to 3 other participants using Finnish Lugers 7.65mm. We all reload, so we end up retrieving and sorting brass.
The .30 Luger case was based on the .30 Borchardt, parent case of the 7,63 Mauser, 9mm Luger and 7.62 Tokarev pistol cartridges.
.30 Luger "7.65x21mm" case length 21.59mm
.30 Mauser "7,63x25mm" case length 25.12mm
7.62 Tokarev "7.62x25mm" case length 25.0mm
Star recommends that their brass for 7,63 Mauser should be checked for trim before before being reloaded for 7.62 Tokarev.
I have shot Fiocchi .30 Mauser in my 7.62x25mm CZ 52 pistol to get brass to reload for my C96 Mauser.
Some people make .30 Mauser cases from .223 Remington or .38 Special cases but it reads like a lot of work. If necessary, I suppose .30 Luger could me made that way if absolutely necessary.