ΔE 8.4, close: similar, with a visible difference side by side. Tyrian Navy is a little darker, more saturated than Panzer Grey. They are different kinds of paint: AMMO by Mig Panzer 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, more saturated than Panzer Grey. They are different kinds of paint.
The same difference applies the other way round: Panzer Grey is a little lighter, more muted.
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 Panzer Grey on the colour wheel See Tyrian Navy on the colour wheel
All matches: Panzer Grey equivalents · Tyrian Navy equivalents