ΔE 13.3, fair: the same colour family, but not a straight swap. Barley Gray BS4800/18B21 is more saturated, warmer than Stormfang.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Barley Gray BS4800/18B21 is more saturated, warmer than Stormfang.
The same difference applies the other way round: Stormfang is more muted, cooler.
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 Stormfang on the colour wheel See Barley Gray BS4800/18B21 on the colour wheel
All matches: Stormfang equivalents · Barley Gray BS4800/18B21 equivalents