ΔE 4.3, very close: most people won’t see a difference side by side. US Olive Drab is a little darker, cooler than RLM 81 Version 1.
Yes, for most jobs. Very close match (ΔE 4). US Olive Drab is a little darker, cooler than RLM 81 Version 1.
The same difference applies the other way round: RLM 81 Version 1 is a little lighter, 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 RLM 81 Version 1 on the colour wheel See US Olive Drab on the colour wheel
All matches: RLM 81 Version 1 equivalents · US Olive Drab equivalents