Its not 80 years old. Thats a new-ish gun as these things go, from 2005.
And every gun system plus its fire control can be very different. One can know how to work A gun but not necessarily THAT gun. And then there are battery and battalion level fire control and operational arrangements
“And then there are battery and battalion level fire control and operational arrangements.”
Exactly - it’s not just “charts and darts” anymore (artillery-speak for manual fire mission calculation).