The 7.62x25mm Tokarev bottlenecked pistol and submachine gun round is a modification of the 7.63x25mm Mauser round, itself a development of the 7.65x25mm Borchardt cartridge. All of them have the same dimensions, despite the different bore designtion. The difference between these three is the powder charge and resulting muzzle energy. While a Tokarev cartridge will fit in the chamber of a 'Broomhandle' Mauser C-96 pistol or a Borchardt C-93 pistol, it will develop pressure in excess of the design of the earlier guns. DO NOT, UNDER ANY CIRCUMSTANCES, try fo fire the Tokarev round in the earlier pistols !!!
The Tokarev round was developed by Fedor Tokarev of the Soviet Union for use with the TT-30 pistol. The bullet diameter is 0.307 inches (7.80mm) and standard weight is about 85 grains. Muzzle velocity is approximately 1600 feet per second and muzzle energy can exceed 500 ft-lbs. The 7.63 Mauser cartridge develops about 1400 fps from a longer barrel, corresponding to a uzzle energy of less than 400 ft lbs. The 7.65 Borchardt cartridge's performance is similar to the 7.63 Mauser.
The 7.62x25mm Tokarev round has been used in many Soviet and East European pistols (most of them close copies of the TT-33) and submachine guns. The earlier Mauser and Borchardt rounds were employed in fewer different designs. Tokarev cartridges are still manufactured by Sellier and Bellot (Czech Republic), Prvi Partizan (Serbia) and Wolf (Russia). Winchester sells Tokarev rounds that are manufactured by Sellier and Bellot. Fiocchi (Italy) manufactures the 7.63 Mauser catridge. The round is also known as 30 Bore in Pakistan.
Note that there is a 7.65x53mm Mauser rifle cartridge that is sometimes called 7.65 Mauser, so confusion with the 7.63 Mauser pistol round (7.63x25mm) is possible.