Twenty-seven-year-old Coles shot 14 out of 16 targets in the gold medal shoot-off to edge out Welsh hope Elena Allen by a single target.
Cypriot Andri Eleftheriou won the bronze medal shoot-off as another Australian, Lauren Mark, made finished in sixth.
Coles, though, appeared set for a big day when she qualified for the event by hitting 70 targets from 75 shots, an effort one shy of Mark’s Commonwealth Games record, set in Manchester in 2002.