ΔE 9.5, close: similar, with a visible difference side by side. Bright Slate Grey is more muted than Space Wolves Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Bright Slate Grey is more muted than Space Wolves Grey.
The same difference applies the other way round: Space Wolves Grey is 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 Space Wolves Grey on the colour wheel See Bright Slate Grey on the colour wheel
All matches: Space Wolves Grey equivalents · Bright Slate Grey equivalents