Somewhere in vid land there is a film taken during a guided tour of a Stern Gang, or Haganah secret ammunition factory. What stood out to me was their chronograph. It was a mechanical type, with a large paper drum affixed to an armature. A calibrated(?) electric motor drove the armature & drum.
This is how I imagined it working:
After firing their test shot, they measured along the circumference & measured the chord the bullet made through the rotating paper drum, & knowing the rpm and physical dimensions of the drum, worked out the velocity of the projectile.
I would imagine they would do this every so often, not sure of the frequency of the test.
Pretty cool analog method of doing things.
According to Earl Narramore, they used the same method at Springfield Armoury in pre electronic days. Another one was two disks mounted on a shaft at a know rotation rate. Measure hole displacement and get out the slide rule.
Grizz
