(Bullet at 200% scale)
The 7.65 x 38 is a bit of an enigma. There is virtually no info or documentation about this cartridge, only anecdotal evidence that has been put in paper along the years. Thanks to Fede from the IAA Forum, this is a chronological compilation of the most relevant sources:
Cartridges for Collectors, Volume I, Fred A. Datig, 1956, p. 41:
No definite information on this cartridge which originated in Switzerland. It is rumored that they were produced on the special order of a foreign power but that, due to international complications, the order was carried out but never delivered. Illustration in Datig shows a loaded cartridge.
Guns, September 1956, cover, p. 16-19, and 70-72:
The dimensions of the Russian all-purpose load correspond within normal manufacturing tolerances with a hitherto-unidentified cartridge known to collectors as the “7.65 x 38 Swiss Machine pistol” type. Jack Brickell of Portland, Oregon, has sold hundreds of these Swiss cartridges to collectors. Enigmatically headstamped “7.65” with no maker’s mark, they were turned out in the German-controlled Swiss Solothurn factory for an unidentified machine pistol, and intended to be used by one side or the other in the Spanish Civil War. The Swiss government officially denies any knowledge of these cartridges, although the new Swiss machine carbine load is also a 38mm case length. However, their base diameter and bullet are like the regular, longer Swiss 7.5mm rifle round. But these pre-war Solothurn Swiss cases are close enough to the Russian to be a twin. The Swiss round was loaded with a steel jacketed 154 grain bullet with a bulky ogive and lead core. Charge was 22.5 grains of a flake powder.
ICCC Bulletin 267-268, March-April 1978, p. 24-25 (comment by Bill Woodin):
This item has been called the 7.65×38 Swiss, for want of a better name; it is an interesting example of something that has turned up in considerable quantities but which, to my knowledge, remains totally unidentified to this day, One theory is that it was for a Solothurn-designed automatic weapon dating from the Spanish Civil War period; however no such weapon has been seen and this appears to be still only a theory,
One of the most frustrating things about this situation, however, is not the identification problem – it’s a people problem! So far as I know, a legitimate 7.65×38 cartridge has never turned up! The correct overall length is not known, nor is the powder charge, The items exist only as primed cases and bullets. They were first imported into this country from Switzerland in 1952 by a well-known dealer, who scrupulously sold them as components only. Then the fellows who can’t stand the sight of empty cases got into the act, and now there are complete rounds all over the place, with varying overall lengths and even with powder! (My feelings about doing this sort of thing are not printable; suffice to say it is not exactly helpful to the serious collector and researcher). The cases themselves were packed in numbers of 100 per each plain cardboard carton, and these in turn were stacked in wood boxes bearing shipping stickers from Lausen, Switzerland. The bullets were packed loose in separate wood boxes, me trail ends there, another mystery among many in the world of the cartridge.”
Assault Rifle Ammunition 5.6mm to 11mm Calibre, P. Labbett, 2000 p. 48-49:
A cartridge (referred to above as the “7.65mm x 38 Unknown”) was apparently manufactured in Switzerland before the 1939- 45 war, probably not by the Swiss State Ammunition Factories but privately. This 7.65mm x 38 round, concerning which much mystery exists, was discovered in quantity in Switzerland in the form of separate primed cases and bullets in a wooden packing box bearing railway despatch markings showing that the despatch point was in the Canton of Basel. It seems reasonable to suppose that the manufacturer was Swiss, even if the actual manufacturer’s identity was deliberately obscured. The cardboard packages within the wooden box each held 100 cartridge cases and were stamped “100” in red and the cardboard was impressed with a stamp [P C F inside triangle]. No loaded rounds are known to exist and the supposition is that these components were intended for a foreign (and discreet) customer, delivery to whom was prevented by the outbreak of war in Europe in 1939.
NZCCC Bulletin 352, January-February 2005, p. 2:
A brass case with cryptic “7 .65” headstamp, brass primer, and C/N clad flat base steel jacket bullet, that even in its abundance, continues to confound research. Cartridges are packed in boxes labelled with a triangle surrounding the letters P o ver C and F.
Although no firearm is known chambered for it and no factory documentation has surfaced, a few details are known. At some time after WW2 a single lot of approx. 10,000 cases and bullets were made. The entire remaining inventory was reportedly purchased from the Solothurn weapons factory by Glasser Co. [W. Glaser] – a gun-shop in Zurich, and from this it can be speculated that they were made at Solothurn, but for who and why remains unknown. The Swiss have experimented extensively with assault rifle cartridges of this type and a number of similar but identified variations are recorded.
Note: This last information was also handwritten by Dimitri Goulas in the cards accompanying his unloaded examples of this cartridge.