ΔE 8.1, close: similar, with a visible difference side by side. A-14 Steel Grey is a little lighter, more muted than Medium Seagray BS381C/637.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). A-14 Steel Grey is a little lighter, more muted than Medium Seagray BS381C/637.
The same difference applies the other way round: Medium Seagray BS381C/637 is a little darker, 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 Medium Seagray BS381C/637 on the colour wheel See A-14 Steel Grey on the colour wheel
All matches: Medium Seagray BS381C/637 equivalents · A-14 Steel Grey equivalents