ΔE 10.3, fair: the same colour family, but not a straight swap. Catachan Flesh is a little darker, more muted than Bullwhack Brown.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Catachan Flesh is a little darker, more muted than Bullwhack Brown.
The same difference applies the other way round: Bullwhack Brown is a little lighter, more saturated.
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 Bullwhack Brown on the colour wheel See Catachan Flesh on the colour wheel
All matches: Bullwhack Brown equivalents · Catachan Flesh equivalents