ΔE 12.8, fair: the same colour family, but not a straight swap. Auric Armour Gold is noticeably darker, more muted than Brass.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Auric Armour Gold is noticeably darker, more muted than Brass.
The same difference applies the other way round: Brass is noticeably lighter, more saturated.
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 Brass on the colour wheel See Auric Armour Gold on the colour wheel
All matches: Brass equivalents · Auric Armour Gold equivalents