When the USA Network began saturating its schedule with reruns of “Wings” in the fall of 1993, something unusual happened. Instead of dropping off in the ratings during their regular primetime run on NBC, the original episodes of “Wings” actually took flight in the Nielsens – the show went from being a modest success to a genuine winner, a vital cog in NBC’s powerhouse Thursday sitcom block.

And “Wings” is not the only example of a longrunning network primetime series that seems to have undergone a Nielsen makeover even after seeding the nightly schedule of a cable network with its reruns.

When the repeats of “Law & Order” began running twice a day on A & E last September, the originals on NBC got a peoplemeter adrenaline shot Wednesday at 10.

And for sheer longevity “Murder She Wrote” has outstripped the most ambitious projections of MCA, its distributor: The show is still going strong on CBS after seven years of continual stripping at 8 p.m. on USA.

The significance of these case histories is that they’re providing new ammunition to cable in its ongoing war with syndication to capture the reruns of hit network primetime series.

“We’re using series like ‘Wings’ and ‘Murder She Wrote’ as illustrations that the network run of a show could be helped by going to cable,” says Neil Hoffman, VP of programming for the USA network.

Hoffman and other cable-network programmers contrast the fate of “Wings” on USA with what would probably have taken place if Paramount Domestic, the distributor, had rejected cable and put the sitcom’s reruns into TV syndication.

“Wings” would have ended up on TV stations covering close to 100% of the U.S., with resultant high syndication ratings, which would have caused the Nielsens for the network primetime originals to fall off, shortening the sitcom’s firstrun life span.

By contrast, the mass-circulation cable networks reach only about 60% of U.S. households and their ratings add up to only a fraction of what a series chalks up on TV stations in syndication, at least in its first year or two.

With “Law & Order,” Brooke Johnson, senior VP of programming and production for A & E, is not surprised that the show has prospered on NBC while its reruns occupy 10 hours a week of A & E’s lineup.

“We’re a nice environment for a quality show like this because we run a lot fewer commercials in an hour than the 14 minutes you see on broadcast TV stations,” she says. (According to the most recent Saatchi & Saatchi cable-network report, A & E schedules 10 minutes of commercial time each hour, eight for the network and two for the local cable system.)

Another plus for the NBC telecast of “Law & Order,” Johnson continues, is that “the typical A & E viewer is someone who doesn’t watch a lot of broadcast TV. This viewer might have seen ‘Law & Order’ for the first time on A & E in reruns and then started seeking out the originals on NBC.”

Preston Beckman, senior VP of program planning and scheduling, West Coast, for NBC Entertainment, agrees. “A & E is a classy network – it pulls viewers who pride themselves on not watching network-primetime television,” Beckman says. Getting “Law & Order” in front of these viewers can only be a plus, he adds, because the A & E runs could serve as a recruiting poster for the NBC telecast.

Lifetime’s stripping of “Unsolved Mysteries” reruns twice a day in the key timeslots of 8 and 11 p.m. could also add another year to its NBC run, Beckman says. NBC moved “Mysteries” to Friday at 8 this season, he says, after “Home Improvement” reruns “kicked the crap out of it” Wednesday at 8 last year. As a result, “Mysteries” has “revived our entire Friday-night schedule,” per Beckman.

For the future, most industry analysts say the top off-network sitcoms such as Carsey-Werner Distribution’s “Grace Under Fire,” Columbia TriStar’s “Mad About You,” and Paramount’s “Frazier” will go to syndication, not cable, because, based on previous track records, their reruns are almost certain to rack up robust Nielsens on TV stations throughout the country. The grossing potential of each of these comedies starts at $1.5 million a half-hour, a figure that’s still way too rich for cable’s blood.

But for the off-network series that have not generated early demand among TV stations in syndication, such as Twentieth TV’s “NYPD Blue,” Columbia TriStar’s “Walker, Texas Ranger” and Viacom’s “Diagnosis: Murder,” the distribs will readily take the reruns to cable, and hope they’ll end up as the “Wings,” “Law & Order” and “Murder She Wrote” of the late ’90s.