ΔE 23.8, loose: different enough that you should pick on purpose. Orange Rust is noticeably lighter, more muted, warmer than Legendary Red.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Orange Rust is noticeably lighter, more muted, warmer than Legendary Red.
The same difference applies the other way round: Legendary Red is noticeably darker, 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 Legendary Red on the colour wheel See Orange Rust on the colour wheel
All matches: Legendary Red equivalents · Orange Rust equivalents