ΔE 11.5, fair: the same colour family, but not a straight swap. Cavalry Brown is noticeably lighter, more muted than Maroon.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Cavalry Brown is noticeably lighter, more muted than Maroon.
The same difference applies the other way round: Maroon is noticeably darker, more saturated.
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 Maroon on the colour wheel See Cavalry Brown on the colour wheel
All matches: Maroon equivalents · Cavalry Brown equivalents