Advocates of gun control traded statistics and insults with gun control opponents before the Montgomery County Council last night as more than 200 jeering and hostile gun owners and sportsmen crowded the council's meeting room in Rockville.

The council's public hearing on a proposal to restrict the sale of ammunition county-wide began with more than 500 angry, shouting gun control opponents, mobilized for the hearing by the powerful National Rifle Association, locked outside the council chambers in the hallway and outside on Maryland Avenue. Six county police officers who blocked the doorway said the fire marshal had ordered the doors locked because the room was already overcrowded.

The bill, introduced by Councilman David Scull, would ban the sale of "fixed ammunition"--excluding flares and signal devices--unless the buyer produced a registration certificate for his handgun. Law enforcement officials and owners of shotguns and rifles would be exempted.

Scull's bill, coming to the council in an election year, has reopened one of thorniest and most emotional issues both in the county and nationwide, with proponents of controls seeing them as a means to halt increasing handgun violence and opponents viewing any form of registration as an unconstitutional first step towards confiscation.

The Scull bill prompted the NRA to mail out a "legislative alert" newsletter to its members, calling the proposal "a devious, roundabout attempt to abolish your firearms rights" and warning members that it was "imperative" to attend the public hearing. The newsletter, signed by Michael J. Lashbrook of the NRA State and Local Affairs Division, was similar to a newsletter that mobilized statewide opposition to Gov. Harry Hughes' gun control bill that went down to defeat in Annapolis last April.

The National Coalition to Ban Handguns, the Women's National Democratic Club, the Alliance for Democratic Reform, and several individuals endorsed the ammunition proposal last night.

"The purpose of this bill is to encourage people to register their handguns," said Michael Beard, a spokesman for the national coalition. "It is not a bullet ban . . . . Montgomery County can join the growing number of American cities like Morton's Grove Ill. , Chicago and San Francisco that have chosen to combat handgun violence."

Dr. Alfred Muller, chairman of the Village Council of Friendship Heights--the tiny community on the District line that passed its own hotly debated bullet ban--said opponents to gun control often appealed to racist or anti-Semitic sentiments.

Muller and the other supporters were roundly booed and hissed by the hostile crowd. There were shouts of "manipulative rhetoric!" and demands that the spokesmen for national groups tell whether they lived in Montgomery County.

Dr. C.P. Chaconas of the county's Citizens for Just Firearm Legislation said registration is the first step to confiscation. "In order to confiscate firearms, as the Nazis did in Germany, you must know who owns them," he said. Chaconas said of Scull and Muller, "I suggest they take up residence in Poland or Russia, where dictators prohibit ordinary citizens from carrying firearms."

Because of the large number who couldn't be admitted to last night's hearing, a second hearing was scheduled for 7:15 p.m. Aug. 5 at Richard Montgomery High School in Rockville.

Thirteen years ago, the Montgomery council rejected a strict gun control ordinance after three days of raucous public hearings at which a large turnout was mobilized by rifle clubs and gun enthusiasts. Among other things, that ordinance would have required all gun owners to obtain "firearm owner's registration cards" valid for five years.

The measure the council rejected in 1968 was based on one drawn up by the Metropolitan Washington Council of Governments following the assassination of Sen. Robert F. Kennedy in June of that year. The defeat of the Montgomery ordinance spelled the disintegration of COG's drive for stringent and uniform area gun control regulations.