NEW York City, already home to some of the strictest gun control laws in the nation, may soon add an assault weapons ban to the list.Just two weeks ago the City Council appeared to be beating a rapid retreat from such a law in the face of strong opposition from gun owners and the National Rifle Association (NRA). City lawmakers are now expected to follow the urging of Mayor David Dinkins and approve a ban as early as July 30. The Big Apple would then join the ranks of more than 30 counties and cities - including Los Angeles, Boston, Atlanta, Denver, and Cleveland - which already have such bans. Both California and New Jersey have statewide bans. Congress is considering one. The Senate voted July 11 to ban 14 kinds of assault weapons. House hearings on similar legislation will begin soon. Behind these recent political moves is a growing public frustration with the proliferation of all kinds of guns - now averaging two per household - and gun-related crime. Recent polls show consistently that 70 percent or more of Americans favor a ban on assault weapons. These rapid-fire guns are a favorite of drug dealers and are frequently linked to the shooting of innocent bystanders. Just last week (July 17) a four-year-old Brooklyn girl shot herself with a 9-millimeter MAC-11 automatic handgun, considered the classic assault pistol, that she found in the trash. New York City has more than 2,100 assault rifles legally registered to individuals. Federal officials say that as many as one million illegal assault weapons may be in national circulation. Though Congress banned 43 kinds of imported assault weapons two years ago, US manufacturers appear to have filled much of the vacuum. Proponents of gun control are encouraged by what they see as a shifting tide in their favor. "There's been a great resurgence of interest at the state and city level in passing gun control legislation in the last three years - we've been doing a whole lot better than the NRA," says Bernard Horn, state legislative director of Handgun Control, Inc. He notes that California, for instance, once a "tough place" for gun control advocates to make progress, is even considering a bill to require all handgun purchasers to pass a safety test. Gun control proponents view national legislation as most effective. They point to the lucrative gunrunning business spurred by differences in state and city laws. Still, they say such laws are useful as models for congressional action. New Jersey's ban on the sale and possession of assault weapons, for instance, is widely regarded as the toughest in the nation. A recent effort by the same legislature to pass a softer replacement bill that would have exempted weapons already registered to gun owners was vetoed this month by Gov. Jim Florio. Police groups have been in the forefront of those pushing for bans on assault weapons. "These military weapons have no place in our cities," says Hubert Williams, president of the Police Foundation. "You still get people talking about their right to have an assault weapon for practice on the range or for hunting purposes.... You might as well dynamite a river, drain it, take out all the fish, and say, "I went fishing - look what I caught." Still, gun owners defend their possession of such weapons as a constitutional right. They say few guns in circulation are assault weapons - accounting for only a small percentage of crimes. Gun control advocates counter that assault weapons, such as the AK-47 used in 1988 by a drifter in Stockton, Calif., to kill five children in a school yard, do far more damage than the usual handgun. "People using them often fire indiscriminately because the weapons aren't very accurate, and innocent people wind up getting shot," says Jeff Muchnick, legislative director of the Coalition to Stop Gun Violence. Still, the fight between gun owners and gun control proponents over banning assault weapons continues strong. New York City's experience is a vivid case in point. The City Council hearing held two weeks ago was punctuated by frequent hissing and boos from NRA supporters, to the point where the sponsor of the bill abruptly moved to delay action pending consideration of a grandfather clause for current owners. Mayor Dinkins, who has been pushing for a strong bill since January, was said to be furious. The new measure, to be discussed by the council's Public Safety Committee on Wednesday, will include a six-month grace period for gun owners who are required to turn in their weapons or render them inoperable but allows no exemption for current gun owners.