I shoot prairie dogs at 400 yards regularly. The film shows a low velocity bullet
from behind
and
later a V-Max from the front.
You are making assumptions about the resolution and the speed of a spring-wound camera that are simply not supportable, even if the camera was not handheld, which it was, and the film interrupted, which it may well have been.
Again, the Zapruder film is as notable for the information which it failed to capture as the information which it did. And the information it did capture is open to multiple interpretations.