7.62 Tokarev is supposed to be .310 bullet diameter.
7.63 Mauser pistol is .309/310

Here's what Starline says about the difference between the Tokarev case & the Mauser case:

7.62X25 TOKAREV BRASS (SMALL PISTOL PRIMER)
7.62mm Tokarev, 7.62x25mm Russian Tokarev
0.958 - 0.964 O.A.L.

This case is very similar, except for the difference in length, to the .30 Mauser. Due to higher operating pressures, if the .30 Mauser cases are fired with hotter 7.62x25 loads in the CZ-52, it will tear the neck off some cases. 30 Mauser O.A.L. is .980" to .985" while 7.62x25 O.A.L. is .958" to .962".

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Starline Brass > 30
30 MAUSER BRASS (SMALL PISTOL PRIMER)
7.63x25mm, 7.63 Mauser
0.979 - 0.986 O.A.L.

This rimless, bottleneck cartridge was developed by American gun designer Hugo Borchardt and was used in the Mauser pistol.


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So I take it that,,
Loads safe for the C-98 Mauser pistol & loaded in 7.63 Mauser cases are apparently fine for the Tokarev pistol. The additional case length causing no problem due to the reduced power load in those cartridges.

BUT if you take the empty 7.62 Mauser cases and load them with Tokarev rated data loads,,the extra case length WILL case problems.

As I said, I've never shot 7.63 Mauser rounds in a Tokarev before. Never owned a Tokarev.
Shooting the Tokarev ammo in a Mauser pistol will cause damage to it's locking lug ribs,,that I have seen. Too much for the old gals to handle.

Tokarevs are able to eat just about anything from what I have seen of them though. Simple and strong.

7.63 Mauser ammo is loaded light as it is intended for but one firearm,,the C96 Broomhandle. Though there are probably others chambered for the round.
Most of the C96's around that are shot are of the Chinese imported variety from the '90's and not the best examples as far as condition and safety.

Most any milsurp ammo around will be berdan primed. Not easily reloaded and the berdan type primers not easily found.

Do some searching on the web and see if using 7.63 MAuser ammo is popular with the Tokarev shooters.
Starline is sold out of Tok brass,,but has the Mauser brass in stock. Same situation as the ammo with the distributors.