ΔE 24.9, loose: different enough that you should pick on purpose. Brass is a little lighter, much more saturated than Heavy Armour.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Brass is a little lighter, much more saturated than Heavy Armour.
The same difference applies the other way round: Heavy Armour is a little darker, 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 Heavy Armour on the colour wheel See Brass on the colour wheel
All matches: Heavy Armour equivalents · Brass equivalents