Wayne LaPierre of the National Rifle Association says 70 senators and 260 representatives have never voted against the gun lobby's positions, but a last-minute NRA about-face is probably responsible for preserving that record.

"I think their influence has deteriorated some," says Sen. J. James Exon, a conservative Nebraska Democrat with a long record of backing the NRA. His view is shared by the NRA's traditional opponents, like Handgun Control Inc., and NRA's more recent antagonists, the nation's major law enforcement organizations.Exon, who parted with the organization over a bill to ban plastic guns that could escape detection at airport metal detectors, said a recent meeting he had with LaPierre subtly communicated that point.

As the NRA's political chief, LaPierre makes frequent visits to Capitol Hill, but Exon says their meeting on May 27 was anything but routine.

The NRA never apologizes for harsh attacks it makes on lawmakers opposing its stands. But here was LaPierre - according to Exon's recollection - admitting the group had gone too far in attacking him for breaking ranks.

LaPierre, director of the NRA's Institute for Legislative Action, denies his comments to Exon amounted to an apology and rejects any view that the pro-gun group has lost a step.

"Our base is as good as gold," LaPierre says. "We're going to be in good shape as long as there are 70 million Americans who own guns and 25 million who hunt. There are 70 senators and 260 House members who have never voted against us."

But Exon described a different mood: "They indicated to me they had fallen down badly in communications. They said they were going to do everything they could to remedy that. They said they may have overreacted in the type of advertising and letter-writing to my constituents."

While Exon believes the NRA has lost influence by attacking its friends, the group's political opponents cite other reasons for their view. Among them:

-The NRA's switch from opposition to support of the bill to ban undetectable plastic guns, legislation that is a top priority of gun control and police groups and is sponsored by NRA nemesis Sen. Howard M. Metzenbaum, D-Ohio.

The NRA changed its mind after police groups successfully lobbied Attorney General Edwin Meese III to support their version of the measure, shaking the NRA's solid core of support in Congress.

LaPierre says the NRA switched only after new language made clear the bill would ban only still non-existent plastic handguns, not existing metal pistols. "A victory for the NRA," LaPierre says.

-A stunning gun control triumph in Maryland, where Gov. William Donald Schaefer, in a ceremony with some 200 police officers, signed a bill May 27 to ban the sale of cheap handguns known as Saturday Night Specials.

LaPierre said the NRA's supporters have begun an effort, successful in its early stages, to place a repeal referendum on the ballot.