ΔE 9.2, close: similar, with a visible difference side by side. Regiment Grey is a little darker, more saturated than RLM 75.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Regiment Grey is a little darker, more saturated than RLM 75.
The same difference applies the other way round: RLM 75 is a little lighter, more muted.
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 75 on the colour wheel See Regiment Grey on the colour wheel
All matches: RLM 75 equivalents · Regiment Grey equivalents