ΔE 6.1, close: similar, with a visible difference side by side. Ratling Grime is a little lighter than Green. They are different kinds of paint: AMMO by Mig Green is an opaque base/layer paint and Citadel Ratling Grime is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 6). Ratling Grime is a little lighter than Green. They are different kinds of paint.
The same difference applies the other way round: Green 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 Green on the colour wheel See Ratling Grime on the colour wheel
All matches: Green equivalents · Ratling Grime equivalents