KV-2 with 107mm ZiS-6 gun tested

KV-2 tank (No. B-9680, produced in December 1940) with a 107 mm ZiS-6 gun installed at factory No. 92, designed for the KV-3 tank (photo at the end of the video: KV-3 wooden model 1:1, May 1941) being tested near the Gorky city in June 1941. (?)