Germany's Sonja Pfeilschifter won the first gold medal of the 2012 ISSF World Cup at the Royal Artillery Barracks in Woolwich.
The 41-year-old world-record holder pipped Yi Siling of China with her last shot of the 10m air rifle final at the Olympic test event.
However, as things stand, Pfeilschifter will not be competing in the same discipline at this summer's showpiece.
"My team won't let me shoot the 10m air rifle event at the Games," she said after the medal ceremony.
"They think I will do better competing only in the 50m rifle 3 position event. But I hope that they will change their mind. I would love to compete at the 10m event here."
Pfeilschifter added: "I really like this venue - it's huge, and looks nice. I just hope it will be warmer at Games time!"
Yi Siling had to settle for silver with Austria's Lisa Ungerank taking bronze.
Jen McIntosh, of Edinburgh, was the highest ranked Brit in 32nd place with Bristol's Jennifer Corish finishing 43rd.
