ΔE 25.5, loose: different enough that you should pick on purpose. Redrum is much more saturated, cooler than Red Copper.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Redrum is much more saturated, cooler than Red Copper.
The same difference applies the other way round: Red Copper is much 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 Red Copper on the colour wheel See Redrum on the colour wheel
All matches: Red Copper equivalents · Redrum equivalents