ΔE 13.8, fair: the same colour family, but not a straight swap. Rusty Metal is much more muted, warmer than Battle Axe Brass.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Rusty Metal is much more muted, warmer than Battle Axe Brass.
The same difference applies the other way round: Battle Axe Brass is much more saturated, 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 Battle Axe Brass on the colour wheel See Rusty Metal on the colour wheel
All matches: Battle Axe Brass equivalents · Rusty Metal equivalents