ΔE 7.1, close: similar, with a visible difference side by side. Stone Grey is a little lighter, more muted, cooler than Grime. They are different kinds of paint: AMMO by Mig Grime is an ink, glaze or transparent paint and Army Painter Stone Grey is an opaque base/layer 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 7). Stone Grey is a little lighter, more muted, cooler than Grime. They are different kinds of paint.
The same difference applies the other way round: Grime is a little darker, more saturated, warmer.
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 Grime on the colour wheel See Stone Grey on the colour wheel
All matches: Grime equivalents · Stone Grey equivalents