I have a book written by a LW Stuka pilot after the war in which he talks about his experiences.  He and his squad were using cannon equipped Stukas to destroy tanks on the Russian front.  I don't remember exactly what the caliber was but it was fairly big.  It would only take a few cannon rounds to destroy a tank.  Apparently this was a fairly common armament option.  I would like to see our Stukas have this available.