I had it used on me to kill my 5inch on a destroyer by a 410 along with de-acking it. The player actually read the readme. I had my twin 5inch on a CV destroyed by a B25 from 3500yds. He opened up from 4000 hitting the CV short of my gun before killing my gun position.
I was inspired to create the B25 gunsight after reading a Marine Air Wing after action report of a B25J attack on a Japanese island position taking out ack. The Marines opened up from 6000yds with their 75mm at 1500ft. The 75mm to 6000yds drops about 1495ft. Give a marine "a gun" no matter how big or small, and he will hit something with it.