Steel Legion Drab vs Smoke Gray

How close are they?

ΔE 15.3, loose: different enough that you should pick on purpose. Smoke Gray is noticeably darker, more muted than Steel Legion Drab.

Can I use Smoke Gray instead of Steel Legion Drab?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Smoke Gray is noticeably darker, more muted than Steel Legion Drab.

Can I use Steel Legion Drab instead of Smoke Gray?

The same difference applies the other way round: Steel Legion Drab is noticeably lighter, 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.