Wyrmling Red vs Primaris Red

How close are they?

ΔE 16.9, loose: different enough that you should pick on purpose. Primaris Red is more saturated, warmer than Wyrmling Red.

Can I use Primaris Red instead of Wyrmling Red?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Primaris Red is more saturated, warmer than Wyrmling Red.

Can I use Wyrmling Red instead of Primaris Red?

The same difference applies the other way round: Wyrmling Red is more muted, cooler.

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.