I read a Spitfire pilot's anecdote somewhere. A Tiger was driving over a hard rock surface when he began strafing it. His rounds bounced off the armor, even around the engines. So he strafed slightly behind it. The rounds hit the rocks and bounced into the weak belly armor. I don't remember what he broke, but it stopped the tank. It was later found with "Good shooting Limey" engraved in the hull.
Who knows if it's true, but...