ΔE 14.2, fair: the same colour family, but not a straight swap. Dark Gunmetal is noticeably darker than Quicksilver.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Dark Gunmetal is noticeably darker than Quicksilver.
The same difference applies the other way round: Quicksilver is noticeably lighter.
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 Quicksilver on the colour wheel See Dark Gunmetal on the colour wheel
All matches: Quicksilver equivalents · Dark Gunmetal equivalents