RAF Dark Camouflage Grey BS381C/629 vs Regiment Grey

How close are they?

ΔE 10.1, fair: the same colour family, but not a straight swap. Regiment Grey is a little darker than RAF Dark Camouflage Grey BS381C/629.

Can I use Regiment Grey instead of RAF Dark Camouflage Grey BS381C/629?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Regiment Grey is a little darker than RAF Dark Camouflage Grey BS381C/629.

Can I use RAF Dark Camouflage Grey BS381C/629 instead of Regiment Grey?

The same difference applies the other way round: RAF Dark Camouflage Grey BS381C/629 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.