Metallic Orange vs Forged Red

How close are they?

ΔE 26.7, loose: different enough that you should pick on purpose. Forged Red is much more muted, cooler than Metallic Orange.

Can I use Forged Red instead of Metallic Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 27). Forged Red is much more muted, cooler than Metallic Orange.

Can I use Metallic Orange instead of Forged Red?

The same difference applies the other way round: Metallic Orange is much more saturated, warmer.

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.