Kerichev at Krasnoye Sormovo in Gorki, did not mate properly with the new gun, apparently being designed around Petrov’s D-5 gun which had been available earlier since it was already in production for the SU-85. Unfortunately, the new turret, designed by V. The new guns were tested at the Gorokhovieskiy Proving Grounds outside Gorki, where Grabin’s ZiS-53 was declared the winner. Siderenko’s team also began design work on their S-18 85 mm gun. Savin when Grabin was shifted to the Central Artillery Design Bureau (TsAKB) in Moscow, and K.
Besides the Grabin and Petrov teams already working on 85 mm guns, Grabin’s bureau at Zavod No 92 in Gorki was turned over to 23-year-old A. Four gun design teams were assigned to a crash program to field an up-armed T-34.
