Broadsword Silver vs Semi Gloss Bright Gun Metal

How close are they?

ΔE 9.8, close: similar, with a visible difference side by side. Semi Gloss Bright Gun Metal is more saturated than Broadsword Silver.

Can I use Semi Gloss Bright Gun Metal instead of Broadsword Silver?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Semi Gloss Bright Gun Metal is more saturated than Broadsword Silver.

Can I use Broadsword Silver instead of Semi Gloss Bright Gun Metal?

The same difference applies the other way round: Broadsword Silver is more muted.

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.