ΔE 8.4, close: similar, with a visible difference side by side. Tyrian Navy is a little darker, cooler than Shadow Grey. They are different kinds of paint: AMMO by Mig Shadow Grey is an opaque base/layer paint and Army Painter Tyrian Navy 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 8). Tyrian Navy is a little darker, cooler than Shadow Grey. They are different kinds of paint.
The same difference applies the other way round: Shadow Grey is a little lighter, 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 Shadow Grey on the colour wheel See Tyrian Navy on the colour wheel
All matches: Shadow Grey equivalents · Tyrian Navy equivalents