I do remember that some allied aces opted for no tracers, for reasons already mentioned.
Adolph Galland seemingly escaped the attention of a few P51's by firing his guns while being chased. He fired his guns (for no reason at all !!) but he thinks that the tracer smoke and discarded shells hit his persuers a/c causing them to break off the chase, thinking there was an axis plane firing at them.
The shell 'streak' (long tracer line) is so unrealistic and a visual effect of film cameras that capture a frame image of 20mS, where the shell streaks by.
It should really be a point (shell image) and nothing else. The tracer smoke trailing behind the shell
