Warm Grey vs Russian AF Grey N.3

How close are they?

ΔE 7.9, close: similar, with a visible difference side by side. Russian AF Grey N.3 is a little lighter than Warm Grey.

Can I use Russian AF Grey N.3 instead of Warm Grey?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Russian AF Grey N.3 is a little lighter than Warm Grey.

Can I use Warm Grey instead of Russian AF Grey N.3?

The same difference applies the other way round: Warm Grey 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.