ΔE 7.7, close: similar, with a visible difference side by side. Brown RLM26 is more muted, warmer than Russet.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Brown RLM26 is more muted, warmer than Russet.
The same difference applies the other way round: Russet is more saturated, 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 Russet on the colour wheel See Brown RLM26 on the colour wheel
All matches: Russet equivalents · Brown RLM26 equivalents