When Soviet firing tests against a captured Tiger I in April '43 showed that the T-34's 76mm gun could not penetrate it, a Soviet 85mm anti-aircraft gun, the M1939, was found capable of doing the job. The gun could penetrate the Tiger I's upper hull armour at 1 km. It was still not enough to match the Tiger, which could destroy the T-34 from a distance of 1.5 to 2 km but it was an improvement.
The T-34/85 had better armour and mobility than the Panzer IV and StuG III. While it could not match the armour or weapons of the Panther and Tiger tanks, its improved firepower made it much more effective than earlier Soviet models, and overall it was more cost-effective than the heaviest German tanks.