Om registered a score of 201.1 in the final.
Daniel Repacholi of Australia took the gold with a new CWG record of 227.2.
Shakil Ahmed of Bangladesh took silver with 220.5.
Defending champion Jitu Rai, the other Indian in the fray, had a disappointing outing.
The reigning Asian Games champion registered a decidedly below par 105 to finish at the bottom of the eight-man final.