J-P - this is totally out of my field and I don’t have very much material on this type of ammunition. Of course, you already have the book “Military rifle and Machine gun Cartridges,” by Huon. It is covered there, but no factory drawings.
The only thing I can add is that these rounds were also manufactured in Mexico. I have some headstamp drawings I made from specimens in the woodin collection, since I was planning on doing an article on all Mexican metallic cartridge headstamps, until it got so many that it became a project almost impossible to publish, requiring slightly over two hundred headstamp drawings, which I have made, not counting dates.
I have three different headstamp drawings, all from “F de M” in Mexico:
- F de M - 13.2 m/m 1936
F de M CAL 13.2-40
I know this isn’t what you have asked for, but hope it is of some help and interest anyway.
There seems to be some question in my files about Sweden using this round. I have a note from a Swedish military ammunition website that says the 13.2 x 99 had been “used in the Airforce for their Automatic cannon M/39.” However, I am not positive they are referring to the Swedish Airforce, since the next entry talks about Italian made ammunition of this caliber (no real information except recording a headstamp of “SMI 1939 IX.” The note goes on that they were “mounted in for example J22, A21/J21 aircraft.” Perhaps one of our airplane afcionados can identify the country discussed by the gun model or the model designations of the aircraft.
That is all I really have on the subject, except what is in Huon’s book and Tony Edwards book.