ΔE 4.0, very close: most people won’t see a difference side by side. Militarum Green is a little darker than Dark Green. They are different kinds of paint: AMMO by Mig Dark Green is an ink, glaze or transparent paint and Citadel Militarum Green is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Yes, for most jobs. Very close match (ΔE 4). Militarum Green is a little darker than Dark Green. They are different kinds of paint.
The same difference applies the other way round: Dark Green is a little lighter.
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 Green on the colour wheel See Militarum Green on the colour wheel
All matches: Dark Green equivalents · Militarum Green equivalents