ΔE 12.5, fair: the same colour family, but not a straight swap. Brown RLM26 is more muted, cooler than Red Oxide.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Brown RLM26 is more muted, cooler than Red Oxide.
The same difference applies the other way round: Red Oxide is more saturated, 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 Red Oxide on the colour wheel See Brown RLM26 on the colour wheel
All matches: Red Oxide equivalents · Brown RLM26 equivalents