Any buff gun position that looks at lead plane, eg No.2 looking at No.1, has the section of the lead plane within the gunsight turn invisible.

Bombcraters visible from cockpit but not through bombsight.
Apologies if already known.
Nvidia FX5200

(I know ... I know) on v56.72 drivers.
(Detail settings at 85% max - draw distance~2 miles).