ΔE 17.6, loose: different enough that you should pick on purpose. Fire Red is a little lighter, cooler than Bestial Brown.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Fire Red is a little lighter, cooler than Bestial Brown.
The same difference applies the other way round: Bestial Brown is a little darker, 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.
See Bestial Brown on the colour wheel See Fire Red on the colour wheel
All matches: Bestial Brown equivalents · Fire Red equivalents