Heavy Metal vs Deathless Metal

How close are they?

ΔE 20.2, loose: different enough that you should pick on purpose. Deathless Metal is a little darker, much more saturated than Heavy Metal.

Can I use Deathless Metal instead of Heavy Metal?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Deathless Metal is a little darker, much more saturated than Heavy Metal.

Can I use Heavy Metal instead of Deathless Metal?

The same difference applies the other way round: Heavy Metal is a little lighter, much 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.