ΔE 7.7, close: similar, with a visible difference side by side. Screaming Skull is a little lighter, more muted, cooler than Light Khaki Drill.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Screaming Skull is a little lighter, more muted, cooler than Light Khaki Drill.
The same difference applies the other way round: Light Khaki Drill is a little darker, more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Light Khaki Drill on the colour wheel See Screaming Skull on the colour wheel
All matches: Light Khaki Drill equivalents · Screaming Skull equivalents