ΔE 16.1, loose: different enough that you should pick on purpose. Prussian Green is a little darker, much more saturated than Militia Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Prussian Green is a little darker, much more saturated than Militia Green.
The same difference applies the other way round: Militia Green is a little lighter, much 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 Militia Green on the colour wheel See Prussian Green on the colour wheel
All matches: Militia Green equivalents · Prussian Green equivalents