Battle Dress Green vs Bright Green

How close are they?

ΔE 17.2, loose: different enough that you should pick on purpose. Bright Green is a little lighter, cooler than Battle Dress Green.

Can I use Bright Green instead of Battle Dress Green?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Bright Green is a little lighter, cooler than Battle Dress Green.

Can I use Battle Dress Green instead of Bright Green?

The same difference applies the other way round: Battle Dress Green is a little darker, 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.