[Spaceships] Conventional and EM Gun ranges in atmosphere?

[Humabout]

Using DouglasCole's formulas, I get a 2cm shell with a 1 mps muzzle velocity having the following stats:

Damage: 69d+2 pi++
Range: 3,800/26,000 yd

This assumes an aspect ratio of 3:1, and DU slug. Increasing the aspect ratio to the upper end of modern 20mm shells (6:1), you get:

Damage: 99d+2 pi++
Range: 9,700/48,000 yd

Running with a muzzle velocity of 2mps, you get the following:

3:1 Aspect Ratio
Damage: 142d+3 pi++
Range: 3,800/35,000 yd

6:1 Aspect Ratio
Damage: 205d pi++
Range: 9,700/64,000 yd