ΔE 8.4, close: similar, with a visible difference side by side. Deep Khaki Drill is a little darker, more muted, warmer than Brownish Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Deep Khaki Drill is a little darker, more muted, warmer than Brownish Green.
The same difference applies the other way round: Brownish Green is a little lighter, more saturated, cooler.
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 Brownish Green on the colour wheel See Deep Khaki Drill on the colour wheel
All matches: Brownish Green equivalents · Deep Khaki Drill equivalents