ΔE 14.9, fair: the same colour family, but not a straight swap. Blackert Brown is a little lighter, more saturated, warmer than Deep Khaki Drill.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Blackert Brown is a little lighter, more saturated, warmer than Deep Khaki Drill.
The same difference applies the other way round: Deep Khaki Drill is a little darker, more muted, 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 Deep Khaki Drill on the colour wheel See Blackert Brown on the colour wheel
All matches: Deep Khaki Drill equivalents · Blackert Brown equivalents