@Ganderite:
That's pretty much exactly what happened. Borchardt designed the gun AND the cartridge. The earliest Borchardt ammno was made by DWM (we think) but as it was the ONLY automatic pistol round they were making, it didn't even have a headstamp. I have a single round of this here, came out of a mixed lot of .303 C Mark II, 7x57 and 7x53 which turned up out of an estate, all stained exactly the same way. Likely it was bringbacks from the Boer War; that's the ony conflict I know of with that mixture of ammo. The Borchardt cartridge evidently had jammed in a gun, but it chambers fine in my Tok.
The Borchardt round actually was a bit on the wimpy side and it was the only round available at that time (1894/95) so that is what Paul Mauser designed his C.95 and C.96 around, just with a bit steamier load for reliability and sales purposes. The Russian Empire and later the Bolsheviks got a large number of C.96 types, so the ammo was familiar in Russia and pretty pervasive. So when the Russians designed their own gun (the Tok), it was designed around a cartridge which they already knew...... just with a little more oomph. As the old Mausers wore out and the Toks came into service, the new gun AND the new ammo became the standard so, no big problems apart from the Mausers jumping a bit much when fired with the new ammo.
Following War Two, the occupation of Eastern Europe and the beginning of the Cold War, the Warsaw Pact was formed and it required everyone's weapons to use Soviet ammunition (and, preferably, Soviet weapons). The Czechs, though, were great developers and didn't want to be bossed around by Hitler OR Stalin. And they were fascinated with the idea of roller-locking, so they designed this big ugly pistol with roller-locking and a series of their own SMGs around an "improved" version of the Soviet pistol/burp gun round, making the ammo hot enough that it really should not be fired in the Russian guns. And THAT is the ammo that people are blithely running through poor little Toks!
Check the figures derived from experiments. The gap between the original Borchardt round and the CZ-52 round is close to 600 ft/sec!!!!! That's like taking an old top-break Smith and running it on a diet of .357 Maggies. Not really a great idea.
But it was all expediency and/or salesmanship and/or bullying and it ended up with ammo on the market which FITS and FIRES in a Tok, but which actually is much too hot. And God help the poor guy who starts running that Czech ammo in a conehammer C.96: he will see his $5k investment down the drain rather quickly.
Hope this helps to clear some of the murk away.
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