ΔE 11.6, fair: the same colour family, but not a straight swap. Brigandine Brown is more muted than Russian Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Brigandine Brown is more muted than Russian Green.
The same difference applies the other way round: Russian Green is 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 Russian Green on the colour wheel See Brigandine Brown on the colour wheel
All matches: Russian Green equivalents · Brigandine Brown equivalents