ΔE 14.4, fair: the same colour family, but not a straight swap. Baneblade Brown is more saturated, warmer than IJN J3 SP (Amber Grey).
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Baneblade Brown is more saturated, warmer than IJN J3 SP (Amber Grey).
The same difference applies the other way round: IJN J3 SP (Amber Grey) is 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 IJN J3 SP (Amber Grey) on the colour wheel See Baneblade Brown on the colour wheel
All matches: IJN J3 SP (Amber Grey) equivalents · Baneblade Brown equivalents