When Hitler invaded Russia the Russian tanks literally could not be penetrated by any gun Germany could muster. Russian tanks could literally run over the anti tank field guns Germany was fielding at the time and it was nearly impossible for their armor to be penetrated. Germany had to field indirect fire artillery guns in an anti-tank role.
The only reason the Soviets had any problems early in the war was due to the purges of military leadership that Stalin performed. It just another example of communism fucking its people over and causing millions of unnecessary deaths when they should have just steamrolled Germany. Germany's early success was not because of their own merits.
Can you give me a link to this?