ΔE 16.0, loose: different enough that you should pick on purpose. Cobalt Violet Grey is a little darker, more muted, warmer than Russ Grey.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Cobalt Violet Grey is a little darker, more muted, warmer than Russ Grey.
The same difference applies the other way round: Russ Grey is a little lighter, 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 Russ Grey on the colour wheel See Cobalt Violet Grey on the colour wheel
All matches: Russ Grey equivalents · Cobalt Violet Grey equivalents