ΔE 18.1, loose: different enough that you should pick on purpose. Sterling Silver is a little darker, much more muted than Gunmetal Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Sterling Silver is a little darker, much more muted than Gunmetal Blue.
The same difference applies the other way round: Gunmetal Blue is a little lighter, much more saturated.
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 Gunmetal Blue on the colour wheel See Sterling Silver on the colour wheel
All matches: Gunmetal Blue equivalents · Sterling Silver equivalents