The 45 mm shells were fired from the standard 45 mm tank gun, the 37 mm shells were fired from the 37 mm Bofors gun in a Vickers 6-ton, both from 100 meters. None of the shells penetrated, but one 45 mm shell, deviously fired into the underside of the turret, managed to rupture the welding seam, jam the turret, and cause some spalling on the inside. The shell did not penetrate. The engine, which was running the whole time, did not stall.
Another test was carried out on T-34s engine, but this one was testing a different kind of protection. Combat in Spain showed that bottles filled with gasoline were an effective weapon against tanks. Soviet testers made no attempts to spare their subjects the brutality of war.