Iron Man 3’ is on its way to a giant weekend at the domestic box office, adding $15.6 million in Thursday evening preview ticket sales to the $345 million the threequel has already grossed overseas.

The weekend total is looking likely to exceed $160 million, with the more optimistic projections putting it near $180 million. If it’s able to hit the $180 million mark, that would give the Robert Downey Jr. starring pic a huge worldwide total in the $650 million range depending on the pic’s overseas total this weekend. Last year, “The Avengers” grossed $156 million in its second weekend overseas.

Iron Man 3” is booked at a huge 4,253 locations, of which 325 are Imax. “The Avengers,” the first Marvel Studios film distributed by Disney, grossed a hard-to-top $207 million in its opening weekend last year, kicking off what turned out to be a respectable but not record-setting $4.28 billion summer.