ΔE 14.3, fair: the same colour family, but not a straight swap. Forged Red is more saturated, cooler than Iridescent Copper Light (Coarse). They are different kinds of paint: Golden Iridescent Copper Light (Coarse) is a pearl paint and Vallejo Forged Red is a metallic, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Forged Red is more saturated, cooler than Iridescent Copper Light (Coarse). They are different kinds of paint.
The same difference applies the other way round: Iridescent Copper Light (Coarse) is more muted, warmer.
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 Iridescent Copper Light (Coarse) on the colour wheel See Forged Red on the colour wheel
All matches: Iridescent Copper Light (Coarse) equivalents · Forged Red equivalents