There was a “Firm” grip applied to the national box office Wednesday as Paramount released its adaptation of the John Grisham bestseller to an opening-day gross of $ 7.2 million, breaking “Jurassic Park’s” stranglehold on the top spot.The studio announced that the film generated $ 7,225,412 from 2,393 prints for averages of $ 3,019. “Jurassic” was second to “The Firm” with a $ 3.75 mil take. “The Firm” ranks as the second-biggest Wednesday opening behind “Terminator 2 : Judgment Day,” released two years ago on the eve of the Independence Day holiday. The latter film preemed to approximately $ 11 million, including $ 2 million from Tuesday night previews. The Memphis-set “Firm” got strong response in the Tennessee city where the first-day cume on six screens was $ 30,353. Memphis averages of $ 5,059 were significantly ahead of the national mean. “We had briefly discussed doing sneaks but historically that’s only worked for a picture with young, male-action appeal,” said Par distribution chief Barry London. “The important decision was really pushing up the picture two days to Wednesday. We wanted to establish it in the marketplace prior to the weekend and I think the figures indicate that strategy has worked.” The Tom Cruise-Gene Hackman starrer had long been considered one of the handful of potential summer blockbusters. Its pedigree of stars, writing and directing talent, and the ongoing appeal of Grisham’s legal thrillers provided the potent marketing tools for a strong launch. Awareness and “want-see” tracking on the film were extremely high, suggesting an opening of about $ 5 million. The Sydney Pollack-directed picture, produced by Scott Rudinand John Davis, had a palpable effect on other key films in the marketplace. The film that took the hardest hit in Tuesday to Wednesday business was Columbia’s “Last Action Hero,” which fell 28%. But its slide was not generally attributed to “The Firm’s” release. Universal’s “Jurassic Park” and Warner Bros.’ “Dennis the Menace” were, not surprisingly, least affected by the new entry. Respectively they saw business ebb back 9% and 5% from Tuesday to Wednesday. Conversely, TriStar’s “Sleepless in Seattle” and Touchstone’s “What’s Love Got to Do With It” saw more erosion in their audience. “Sleepless” was down 20% and “What’s Love” rolled back 26%. Wednesday business had “Sleepless” third on a gross of $ 2.27 million. “Dennis” was fourth with $ 1.72 million followed by “Action Hero’s”$ 800,000 and “What’s Love” at about $ 600,000. Paramount’s London maintained a cautious stance going into the weekend. He said there was a “strong possibility” the Paramount film would be first in the marketplace. Other trackers insisted any such discussion was ludicrous. Based upon opening-day figures and tracking studies available Thursday, the film will have a healthy spread over “Jurassic” for the four-day period. “The Firm” is expected to gross more than $ 50 million by Monday.