Heading had gone into the second day of action in the joint-lead, but could not hold on to that at the Belmont Shooting Centre as Wixey overtook the 2010 champion for gold.
Wixey - whose best men's trap showing in his four previous Commonwealth campaigns was a fourth-placed finish in Manchester 16 years ago - broke the Games record with a mark of 46 to claim the biggest title of his career.
Heading was forced to settle for silver, while fellow overnight leader Brian Galea of Malta ended the competition in third to claim the bronze medal.
England's Edward Ling - a bronze medallist at the Rio Olympics in 2016 - missed out on a place on the podium, meanwhile, finishing fourth with a final-day score of 28.
Australia's Mitchell Iles-Crevatin was also in the mix for medals heading into the second day, but having qualified for the final he could only finish fifth.