ΔE 6.3, close: similar, with a visible difference side by side. Astrogranite is a little darker, more muted than Grau RLM 02. They are different kinds of paint: AMMO by Mig Grau RLM 02 is an opaque base/layer paint and Citadel Astrogranite is a technical paint or medium, 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). Astrogranite is a little darker, more muted than Grau RLM 02. They are different kinds of paint.
The same difference applies the other way round: Grau RLM 02 is a little lighter, 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.
See Grau RLM 02 on the colour wheel See Astrogranite on the colour wheel
All matches: Grau RLM 02 equivalents · Astrogranite equivalents