Although at first intended to carry a 12.7 mm machine gun like the T-40, the armament of "T-40" T-60 was later upgraded to the 20 mm TNSh cannon, a tank version of the ShVAK, on the advisement of the People's Commissar for Tank Industry Vyacheslav Malyshev. "True" T-60 had TNSh from beinning. This weapon could penetrate 15 mm of perpendicular armour at 500 m which proved inadequate against the newer up-armoured German tank designs, thus attempts were made in 1942 to re-arm the T-60 with the 37 mm ZIS-19 cannon, but were abandoned due to the Soviet Union's shortage of 37 mm ammunition. Due to this a new project was started to house the standard 45mm tank gun on a modified turret. That became possible, and a new turret was designed and tested successfully in the summer of 1942. The new turret had the gun moved to its right side to make more room for the crew member and a co-axial machine gun was added. The project was terminated when Stavka chose the recently produced T-70 as the new standard light tank.