ΔE 21.1, loose: different enough that you should pick on purpose. Feral Brown is noticeably darker, much more muted, warmer than Chimera Red.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Feral Brown is noticeably darker, much more muted, warmer than Chimera Red.
The same difference applies the other way round: Chimera Red is noticeably lighter, much more saturated, 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.
See Chimera Red on the colour wheel See Feral Brown on the colour wheel
All matches: Chimera Red equivalents · Feral Brown equivalents