ΔE 10.3, fair: the same colour family, but not a straight swap. Hammered Copper is a little lighter, more saturated than Magnesium.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Hammered Copper is a little lighter, more saturated than Magnesium.
The same difference applies the other way round: Magnesium is a little darker, 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 Magnesium on the colour wheel See Hammered Copper on the colour wheel
All matches: Magnesium equivalents · Hammered Copper equivalents