ΔE 6.6, close: similar, with a visible difference side by side. Brigandine Brown is a little lighter than Rubber Black.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Brigandine Brown is a little lighter than Rubber Black.
The same difference applies the other way round: Rubber Black is a little darker.
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 Rubber Black on the colour wheel See Brigandine Brown on the colour wheel
All matches: Rubber Black equivalents · Brigandine Brown equivalents