ΔE 8.0, close: similar, with a visible difference side by side. Grey Castle is a little darker than ADC Grey FS 16473.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Grey Castle is a little darker than ADC Grey FS 16473.
The same difference applies the other way round: ADC Grey FS 16473 is a little lighter.
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 ADC Grey FS 16473 on the colour wheel See Grey Castle on the colour wheel
All matches: ADC Grey FS 16473 equivalents · Grey Castle equivalents