Even if "Stripes" has been quick enough to beat "Private Benjamin" to the marketplace, it would never have made much sense to build an updated service comedy around the idea of Bill Murray as a misfit buck private. Opening today at area theaters, "Stripes" squanders at least an hour belaboring situations contradicted from the outset by Murray's personality. The premise and star remain out of whack until the rambling, diffuse screenplay finally struggles beyond basic training.

Too old and smugly knowing to be credible as a brash newcomer to the service -- a semi-bohemian cabbie named John Winger, who enlists impulsively after his life seems to fall apart on a single day -- Murray would be easier to accept as a veteran service sharpie or fixer. Instead of following in the footsteps of all the comic raw recruits from Charlie Chaplin in "Shoulder Arms" to Andy Griffith in "No Time for Sergeants," an insinuating wise guy like Murray should take his cues from Phil Silvers' Sgt. Bilko or Jack Lemmon's wily Pvt. Hogan in the winning yet seldom revived "Operation Mad Ball" of 1957. It's really a waste of time maneuvering Murray into uniform when he'd look more comfortable as a sneaky, smarty-pants career soldier of some kind. If he were a devious noncom like Bilko even the title might make sense.

If you're fond of Murray, the miscalculation may be excused as an acceptable bad excuse for gratuitous laughs. Scattered as they are, certain moments bear his inimitable, appealing stamp. For example, on the morning of a 10-mile march, Murray glares at the downpour outside and makes a modest suggestion to the platoon's drill instructor. Warren Oates: "Sergeant, I think this is a bad time to march. It is the cold and flu season." I'm not sure anyone but Murray would interject the following doubletake aside into a pep talk for his despondent comrades: "We're American soldiers! We're ten-and-one!" When he gets in the oratorical groove, he has an uncanny ability to slip screwball hyperbole past you.

Still, the foundation for this style of hip facetiousness is shakier than it ought to be. The willing suspension of disbelief takes an additional beating when Harold Ramis, cast as his best friend, Russell Zisskey, agrees to join up too. Apart from humoring buddy Winger, Zisskey has no earthly reason for enlisting. It's almost as if "Stripes" were intended to make "Private Benjamin" look realistic.

Already fighting a losing battle against incredulity, the basic training sequences slip and slide into assorted detours, including miserable episodes in which Murray and Oates come to blows and a porky platoon member played by John Candy defeats a team of vicious female mud wrestlers at a saloon. The slack continuity suggests a movie improvised around a loose script or fragments of several scripts. It's typical of the makeshift atmosphere that a sure-fire comic set piece -- Murray leading the platoon in a jive manual of arms that wows the post on graduation day -- should emerge from a dumb premise. The night before achieving this miracle of precision, the men are still too clumsy to master the conventional manual of arms.

Murray and director Ivan Reitman displayed far better coordination on their first comedy, the cheerful summer camp farce "Meatballs." Cast as a senior counselor and resident inspirational wit at a camp full of chronic underachievers. Murray seemed to improvise brilliant monologues from a position of authority held casually and without hypocrisy.

Given the nature of his earlier role, it's baffling that Murray and Reitman would overlook its strategic advantages when preparing "Stripes." Unlike Goldie Hawn, Murray seems a total fraud if required to play dumb. He's nothing if not an ingratiating know-it-all, an ace manipulator and agitator.

"Stripes" collects itself in time for a sustained zany finale. Stationed in Italy, Winger and Zisskey borrow a top-secret experimental vehicle -- an armored camper van -- for a weekend frolic with their girlfriends, MP's improbably embodied by P. J. Soles and Sean Young. Discovering the loss, their frantic, inept captain (John Larroquette) leads the platoon on an impulsive search that blindly strays across the Czech border. Winger then suggests a rescue mission in the impregnable, hi-tech RV, brushing aside Zisskey's worries with the blithe assurance. "We're talking about Czechoslovakia! It's like going into Wisconsin!"

Despite the alarming implications for the Spirit of Detente, wherever it is, the Winger incursion is an amusing cartoon spree, with Reitman somehow contriving to expend an enormous amount of colorful firepower without anyone getting seriously harmed. Joseph P. Flaherty and Nick Toth contribute a funny turn as Russian border guards left in dumbfounded custody of a demolished station. As a kicker, the movie even throws in a mischievous spoof of the hoopla that attended the homecoming of the hostages. A little late to get rolling, but, better late than never.