ΔE 35.2, loose: different enough that you should pick on purpose. Beetle Green is a little lighter, much more saturated, warmer than Semi Gloss Bright Gun Metal.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 35). Beetle Green is a little lighter, much more saturated, warmer than Semi Gloss Bright Gun Metal.
The same difference applies the other way round: Semi Gloss Bright Gun Metal is a little darker, much more muted, cooler.
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 Semi Gloss Bright Gun Metal on the colour wheel See Beetle Green on the colour wheel
All matches: Semi Gloss Bright Gun Metal equivalents · Beetle Green equivalents