Even in limited release, “The Fighter’’ packed a serious punch at the box office over the weekend. Director David O. Russell’s movie starring Mark Wahlberg as Lowell-bred brawler “Irish’’ Micky Ward and Christian Bale as Micky’s half-brother Dicky Eklund grossed $320,000 in just four theaters. “The Fighter’’ opens in 2,200 screens Friday and is already being mentioned as an Oscar contender, primarily for the performances of Bale and Melissa Leo, who plays Micky and Dicky’s mom, Alice Ward.



