i believe that they can find some prototype from between ww1 and post ww2 to add to the game 
nah… they have different rate of fire cause devs decided to do so and not cause of cartridge. mauser and tokarev cartridges are more or less same. there is debate on whether original tokarev had 10% more load vs mauser or if it had same load. but regardless of that, they both had ~same ballistic properties when tested.
here is from similar disccusion: Difference between 7.63×25 and 7.62×25 - #26 by JPeelen - General Ammunition Discussion - International Ammunition Association Web Forum
According to Russian manuals for the Mauser pistol (dated 1933-1938) and TT pistol (dated 1935-1940), this is the ballistic performance of the Mauser and TT cartridges:
Mauser = bullet 5,5 g, propellant 0,5 g, mv 425 m/s, barrel length 140 mm (1933).
Mauser = bullet 5,5 g, propellant 0,5 g, mv 400 m/s, barrel length 98 mm (1938).
TT = bullet 5,52 g, propellant 0,59 g, mv 420 m/s, barrel length 116 mm (1935-1940).
For comparison, here is the ballistic performance of the 7.63 mm Mauser cartridge published by DWM during the 1930’s:
1930: bullet 5,5 g, propellant 0,53 g, mv 420 m/s, barrel lenght 140 mm.
1934: bullet 5,5 g, propellant 0,52 g, mv 443 m/s, barrel lenght 140 mm, pressure 2500 kg/cm2.
1937: Same as above.
if you take russian data into account then equivalent muzzle velocity for equivalent ~116mm mauser would be ~412m/s. so according to their measurements ~20% extra load gives ~2% extra muzzle velocity, which would mean that their propellant is weaker than german.
btw i dove into this rabbit hole when i was bored some 2-3 years ago cause of ppsh41/mp717r debate and there is no conclusive evidence either way(well at least on english with original ammo). lots of countries added extra load post ww2 to tokarev and post ww2 american made mauser was apparently loaded with less load and almost all literature quotes values for post ww2 cartridges.
