ΔE 7.6, close: similar, with a visible difference side by side. Dark Green RLM71 is a little lighter, more muted than Dark Olive Drab.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Dark Green RLM71 is a little lighter, more muted than Dark Olive Drab.
The same difference applies the other way round: Dark Olive Drab is a little 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 Dark Olive Drab on the colour wheel See Dark Green RLM71 on the colour wheel
All matches: Dark Olive Drab equivalents · Dark Green RLM71 equivalents