Comments by "Sar Jim" (@sarjim4381) on "Swedish Antiaircraft Artillery: Bofors 40mm Automatic Gun M1" video.

  1. The US Navy developed the Mark 57 Gunfire Control System late in the war. It wasn't really a better optical control system than the original Mark 51 director, but it added radar for use in reduced visibility conditions. One Mark 57 then controlled four Mark 51 directors. The Mark 51's were still useful in good visibility, but any massed gunfire lasting more than a minute or so caused the targets to be obscured by gun smoke. That's when the Mark 57 took over and controlled the four 40 mm quad mounts instead of the four separate Mark 51 directors.
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