ΔE 18.2, loose: different enough that you should pick on purpose. Semi Gloss Bright Gun Metal is a little lighter, much more muted, cooler than Azure Magic.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Semi Gloss Bright Gun Metal is a little lighter, much more muted, cooler than Azure Magic.
The same difference applies the other way round: Azure Magic is a little darker, much more saturated, 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 Azure Magic on the colour wheel See Semi Gloss Bright Gun Metal on the colour wheel
All matches: Azure Magic equivalents · Semi Gloss Bright Gun Metal equivalents