The Lionsgate release led the last weekend of a fairly quiet season for Hollywood, with attendance down 4 percent from summer 2011, according to box-office tracker Hollywood.com.
Opening in second-place with $9.7 million was the Weinstein Co. bootlegging drama "Lawless," starring Shia LaBeouf.
"The Expendables 2" pulled in $8.8 million, falling to No. 3 after two weekends as the top draw at theaters.
Expanding to more theaters, the anti-Barack Obama documentary "2016: Obama's America" added to its haul as a surprise mini-hit leading up the presidential election. "Obama's America" was No. 9 with $5.1 million, raising its domestic total to $18.3 million.