ΔE 20.5, loose: different enough that you should pick on purpose. Orange Rust is a little darker, much more saturated, cooler than Orange Magma.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Orange Rust is a little darker, much more saturated, cooler than Orange Magma.
The same difference applies the other way round: Orange Magma is a little lighter, 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 Orange Magma on the colour wheel See Orange Rust on the colour wheel
All matches: Orange Magma equivalents · Orange Rust equivalents