ΔE 18.5, loose: different enough that you should pick on purpose. Trollblood Base is a little darker, much more saturated than Gryph-Charger Grey. They are different kinds of paint: Citadel Gryph-Charger Grey is a one-coat contrast-style paint and Formula P3 Trollblood Base is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Trollblood Base is a little darker, much more saturated than Gryph-Charger Grey. They are different kinds of paint.
The same difference applies the other way round: Gryph-Charger Grey is a little lighter, much 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 Gryph-Charger Grey on the colour wheel See Trollblood Base on the colour wheel
All matches: Gryph-Charger Grey equivalents · Trollblood Base equivalents