ΔE 22.1, loose: different enough that you should pick on purpose. Flat Red is a little lighter, much more saturated than Dragon Red.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Flat Red is a little lighter, much more saturated than Dragon Red.
The same difference applies the other way round: Dragon Red is a little darker, 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.
See Dragon Red on the colour wheel See Flat Red on the colour wheel
All matches: Dragon Red equivalents · Flat Red equivalents