ΔE 9.8, close: similar, with a visible difference side by side. USAAF Light Gray is a little darker, more saturated than Bright Neutral Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). USAAF Light Gray is a little darker, more saturated than Bright Neutral Grey.
The same difference applies the other way round: Bright Neutral Grey is a little lighter, 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 Bright Neutral Grey on the colour wheel See USAAF Light Gray on the colour wheel
All matches: Bright Neutral Grey equivalents · USAAF Light Gray equivalents