Even though the tank guns of 45mm calibre and smaller were considered obsolescent, the experimental work on them continued. This happened because RKKA accepted the T-40 Light Amphibious Tank into service, which had an armament consisting of a 12.7mm machine-gun DK (and later — DShK) already considered insufficient in 1940.

As far back as in 1939, OKB #16 headed by Ya.G. Taubin was ordered to develop a clip-loading 23mm automatic gun for the T-40 tank. The prototype gun received the designation PT-23TB (23mm Tank Gun of Taubin and Baburin design), and was built «in metal» by OKB #16 on the basis of the design of the light 23mm infantry anti-tank/anti-aircraft gun. An experimental tank, whose turret contained the only experimental prototype of the gun, was made operational, and used for firing range trials in December 1940.

Nevertheless, in implementing the instruction of the People's Commissariat of Armament, on 25th January, 1941, the gun was removed from the tank and sent to Factory #5 where work on the armament for armoured snowmobiles for NKVD was underway. Soon, the Head of the Design Bureau Taubin was relieved of duty and arrested, and all the advanced work on the PT-23TB gun was stopped.

Muzzle velocity of the armor-piercing projectile is 830 m/s.

Translation: Rodion Podorozhny
Proof-read: Chris Amundson
Sources: «Artillerijskoye Vooruzhevie Sovetskikh Tankov 1940-1945» Armada-Vertical, #4, 1999