Traitor Red vs Battlefield Brown

How close are they?

ΔE 6.3, close: similar, with a visible difference side by side. Battlefield Brown is more muted than Traitor Red.

Can I use Battlefield Brown instead of Traitor Red?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Battlefield Brown is more muted than Traitor Red.

Can I use Traitor Red instead of Battlefield Brown?

The same difference applies the other way round: Traitor Red 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.