ΔE 9.3, close: similar, with a visible difference side by side. NATO Green is a little darker, more saturated than Ashen Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). NATO Green is a little darker, more saturated than Ashen Grey.
The same difference applies the other way round: Ashen Grey is a little lighter, more muted.
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 Ashen Grey on the colour wheel See NATO Green on the colour wheel
All matches: Ashen Grey equivalents · NATO Green equivalents