ΔE 14.5, fair: the same colour family, but not a straight swap. Primer Dark Neutral Grey is much more muted than Stirland Mud.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Primer Dark Neutral Grey is much more muted than Stirland Mud.
The same difference applies the other way round: Stirland Mud is much more saturated.
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 Stirland Mud on the colour wheel See Primer Dark Neutral Grey on the colour wheel
All matches: Stirland Mud equivalents · Primer Dark Neutral Grey equivalents