ΔE 12.5, fair: the same colour family, but not a straight swap. Army Green is a little darker, more muted, warmer than Green Base.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Army Green is a little darker, more muted, warmer than Green Base.
The same difference applies the other way round: Green Base is a little lighter, more saturated, cooler.
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 Green Base on the colour wheel See Army Green on the colour wheel
All matches: Green Base equivalents · Army Green equivalents