nonoht,
as a side note:
My uncle was a engineer/gunner in a He111 (KG51), I talked to him yesterday and he said when they got their (forward firing)20mm cannons, they used them to "scare away" attacking fighters. The HE-shells had a self fusing distance of 700meters and they just "sprayed and prayed" some rounds into the flight path of the attacker. He said the sound of the shrapnell (?) fragments hitting the airframe caused most fighters to break up with their attack.
He also said, in the late years of WWII they used the 111 as ground attack plane. It had 4 forward firing 20mm cannons, they did low level attacks on trains in Russia. He keeps telling me the story of one guy, who had mounted 13 (!) forward firing MG's and cannons and used that thing for ship attacks.
I don't know if you can sink a destroyer with some MG's but the hail storm of more than 100 bullets a second hitting the deck shure must have scared the sh*t out of the poor sailors

BTW this guy got shot down anyway
May be it'is the wrong thread for this, but my uncle's job was also to install the "ADLER Zielgerät" into FW190's in the last days of war. This was the German variant of a gyroscopic gunsight. It had a "electronic" computing device with no moving parts (besides the gyro) and was used for precise high deflection shooting against buffs (side attacks). If anyone is interrested, I have a rather bad photograph of that thing built into a trainer...