ΔE 10.6, fair: the same colour family, but not a straight swap. Ardennes Green is a little lighter, more muted, cooler than Steel Helmet Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Ardennes Green is a little lighter, more muted, cooler than Steel Helmet Green.
The same difference applies the other way round: Steel Helmet Green is a little darker, more saturated, warmer.
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 Steel Helmet Green on the colour wheel See Ardennes Green on the colour wheel
All matches: Steel Helmet Green equivalents · Ardennes Green equivalents