ΔE 12.8, fair: the same colour family, but not a straight swap. Rucksack Tan is noticeably darker, more saturated than Webbing Khaki.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Rucksack Tan is noticeably darker, more saturated than Webbing Khaki.
The same difference applies the other way round: Webbing Khaki is noticeably 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 Webbing Khaki on the colour wheel See Rucksack Tan on the colour wheel
All matches: Webbing Khaki equivalents · Rucksack Tan equivalents