My source says:
"About 700 served on the Eastern Front, many having 50mm and 75mm guns for tank-busting; a few nervously bombed Britain in 400mph shallow dives."
What the hell is that kind of source? Bob's Big Book of Airplanes? Some kiddie coloring book?
A few? Nervously bombing? In shallow dives? What....
Ok. During the mini blitz 3./KG 100 was the first Heinkel 177 unit flying against Britain, target London. I./KG100 joined them in these operations. One tactic was to bomb target marked by pathfinders from 5000 meters, flying in 560km/h shallow dive in descent rate of 200m/minute. This was not a "nervous dive" but a very fast speed bombing run that allowed the bombers to hit target in high speed and get out fast, making effective interception very hard. Alongside London, Heinkels targeted for example Hull and Bristol.
And 50mm guns for tank busting? Never happened. 75mm, yes. A-3/R5. Heavy fighter, designed for Anti Air, some sources claim also used for anti tank. Doubtful. Very few build as such, anyway. A-1/U1 was more interesting, twin 30 mm MK101s for anti bomber work.
More interesting versions, if talking about special uses, were A3-/R3 and forward, used as anti shipping missile carriers. Those were nice planes, used for patrolling and anti convoy raids in the Atlantic and Mediterranean.