ΔE 6.5, close: similar, with a visible difference side by side. Eshin Grey is a little darker than Hell Bent for Leather.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Eshin Grey is a little darker than Hell Bent for Leather.
The same difference applies the other way round: Hell Bent for Leather is a little lighter.
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 Hell Bent for Leather on the colour wheel See Eshin Grey on the colour wheel
All matches: Hell Bent for Leather equivalents · Eshin Grey equivalents