TKB-22
(army accepted as TKS)

Cartridge: 7,62х39 (9х21)
Action: Gas-operated, vertical sliding breech-block system
Length: 535 mm
Barrel length: 430 mm
Weight: 2,6 (2,4) kg
Firing rate: 560 shots per minute (580 shots per minute)
Feed: 30 round clip (20 round clip)

See PPK submachine-gun specifications in brackets..

TKB-22 assault rifle designed by A.G. Korobov also participated in the competition organized by the USSR Ministry of Defense that was won by the Tkachev assault rifle. It showed better ballistic results, so its designer was asked to continue his work keeping the noted drawbacks in mind. The work on improving the weapon was completed in time, and the new prototype was presented again.

The composite body of the rifle was swapped for a sturdier one stamped out of aluminum alloy. The barrel length was slightly increased to allow for outer rifling for attaching a suppressor while the handle was moved back to allow for installation of the perspective noiseless grenade launcher BS-1. This variant of the weapon has been designated as TKS and was given to special units of the army and MGB.

Good handling of the weapon in burst mode and its reliability attracted the attention of army authorities once again, and the designer was asked to create a sub-machine gun firing 9x21 (SP-10/11/12) cartridges on its base. These rounds were more effective against protected targets including mutated animals. The Korobov sub-machine gun (Russian: PPK) looked very much like its predecessor, differing only in magazine use (straight 20 rounds clips).