bustr, do you by any chance have any info on the sight that was used for the B-25H and its 75mm cannon?
ack-ack
You won't like this answer.
It had the standard 70Mil reticle. The dial on the left side of the N-3C body is an early war A1 tilting sight head. You could adjust for 14Mil of deflection for the center dot. The copilot read off a chart for speed, alt and range, while the pilot attempted to make it work. Maximum range was 4000 yards for shipping targets and they missed a lot.
Eventually an AN/APQ-13 Radar ranging unit was developed that automatically tilted the sight head improving shipping hits at 4000 yards to about 9 in 20 near the end of the war. The rule for accurate manual range shooting with the 75-mm T13E1 was really 2000 yards pulling up at 1000 yards.
I include a 70Mil ring in my historic pac with 10Mil tick marks to fill in for the A1 tilting sight head.