This big-budget L.A. police movie is inspired by the old television series, but in terms of sheer firepower it makes the ABC “S.W.A.T.” of 1975-76 look like “Mary Poppins,” despite the fact that the Spelling-Goldberg skein was criticized at the time for its level of violence. How things have changed. The new version is in some respects a typically bombastic summer blockbuster, with lots of shootouts, chases and fisticuffs and an extraordinarily high decibel level (not just the gunfire, but a score–composed of both pop tunes and background music by Elliot Goldenthal–that’s not only extraordinarily loud but, frankly, second-rate).

And yet there’s a good deal of time-warpy joyfulness to first-time director Clark Johnson’s flick. “S.W.A.T.” may be a lot sleeker and bigger than its small-screen counterpart, and it may have a hipper, jokier attitude, but in spirit and content it’s not all that far removed from the old show. That’s because David Ayer and David McKenna have hewed fairly closely to the tough-sergeant-molds-his-rookies scenario of the series. This is a rougher, more ethnically diverse group than originally, of course, and the language they use is more colorful and street-wise; the cops also suffer from tensions, personal and professional, that weren’t part of the old mix. But the camaraderie that gradually grows among the team members has a familiar ring, and to accentuate the paternity the script even preserves some of the original character names (“Hondo” Harrelson, Jim Street, “Deke” Kaye, T.J. McCabe) and periodically brings in the mid-seventies theme song; on one occasion a snippet from an episode showcasing Steve Forrest appears, too. You might regret that it goes so far as to employ the hoary device of the inept captain who’s antagonistic to the team and always interferes in its doings, but if you remember the show with any affection at all, you’ll probably appreciate most of these touches.

And even if not, you may be taken by the relative simplicity and straightforwardness of the movie. At a time when action pictures have gotten so huge and stunt-oriented that their only function seems to be to blow your mind with ever more awesome, literally incredible set pieces, “S.W.A.T.” takes a more down-to-earth approach. It’s hardly a gentle flick–there’s plenty of macho heroics and humor–but all of it is grounded in a semblance of reality. The training sessions in which Hondo molds his chosen few to the pitch of readiness are brazenly John Fordish, but don’t turn the characters into super-beings. And even in the last act, when the script whips up a large-scale version of “Assault on Precinct 13” as its big finale, introducing an international crime boss who offers a hundred million bucks to anybody who can free him from police custody after he’s jailed on a minor charge, the mayhem that follows isn’t physically beyond the pale–it’s heightened and implausible, to be sure, but still within the realm of the barely possible. (Compare the highway chase scenes in “The Matrix Reloaded,” “Terminator 3: Rise of the Machines” and, especially, “Bad Boys II,” and you’ll see what I mean.) And wonder of wonders, the team actually makes bad choices and blunders from time to time–members can even go bad or get injured.

The cast does its bit, too. Samuel L. Jackson, who had fun reviving another old chestnut, “Shaft,” a few years back, makes a suitably gruff, ramrod-straight Hondo, and Colin Farrell’s cocksure manner is well employed as a more driven Jim Street than the late Robert Urich played. The rest of the team, unfortunately, isn’t in the same league. James Todd Smith (aka LL Cool J) is the best of them, continuing to show real screen presence; but Michelle Rodriguez, Josh Charles and Brian Van Holt barely get by. At the opposite end of the moral scale, Olivier Martinez can’t do a great deal with the stock part of the menacing mobster, but Jeremy Renner is appropriately smarmy as Street’s headstrong, duplicitous former partner. It’s hard to recognize him as the same fellow whose quietly controlled performance in “Dahmer” was so deeply chilling.

“S.W.A.T.” looks good–it’s consistently well-appointed, and filmed in mostly fine widescreen by Gabriel Beristain (though some of the confrontations at the end are murky, played out as they are in near-darkness). Johnson, who’s done some solid TV work as a director, shows his acting roots with a style that’s less hyperkinetic than is customary nowadays and more considerate of the people on the screen. His choices are complemented by Michael Tronick’s editing, which shuns the perpetual three-second cuts of most contemporary shoot-’em-ups in favor of a cleaner, leaner, more viewer-friendly approach.

All this makes for an action movie that, despite its modern sheen, has an almost charmingly old-fashioned feel. At the end–following an obligatory over-the-top confrontation, this time between a car and an airplane–it even finds room for a chestnut hardly employed anymore without a satirical edge–the one in which the hero tosses away his gun so that he and the villain can go mano-a-mano in a fair fight. Here, though, the convention is played straight. If the idea of seeing a staple like that again appeals to you, you should find “S.W.A.T.” an agreeable throwback. If not, there’s always the crude excess of a “Bad Boys II” to meet your needs.