The House yesterday approved tough mandatory penalties for young people convicted of using a gun in a crime but rejected new curbs on the entertainment media, as lawmakers began work on a wide-ranging package of measures aimed at curbing youth violence.

The action came during an emotional, day-long House debate over juvenile justice legislation that has assumed center stage on Capitol Hill. The debate will continue today when lawmakers consider a series of closely contested measures on gun control, including competing plans to require background checks at gun shows.

At stake yesterday was a juvenile justice bill that had stalled for two years until the Littleton, Colo., school shootings in April. The basic measure would provide an extra $1.5 billion to the states to help combat juvenile crime, but lawmakers worked though the evening on a series of amendments offering a variety of additional approaches to the problem. Final passage of the overall bill is not expected until today, or possibly Friday.

On one of the most closely watched amendments, lawmakers approved 249 to 181 a plan by Rep. Bill McCollum (R-Fla.) to impose stricter penalties on juvenile offenders. Under the measure, the maximum penalty for juveniles convicted of illegally possessing a firearm would be increased to one year, while those convicted of possessing a firearm with the intent of taking it to school would face a maximum of five years. Also, juveniles as young as 14 could be tried as adults.

While members of both parties appeared eager to get tough with juvenile offenders, an even larger bipartisan majority rejected a proposal to crack down on the entertainment industry -- which many Republicans have tried to finger as the culprit in Littleton.

On a 282 to 146 vote, lawmakers shot down a proposal by Judiciary Committee Chairman Henry J. Hyde (R-Ill.) that would have made it a crime to distribute or sell to minors any movies, video games, books, magazines or other materials that contain explicitly sexual or violent material.

Hyde portrayed the measure as necessary to "slow the flood of toxic waste into our kids' minds," but many other lawmakers -- backed by an aggressive lobbying campaign by the entertainment industry -- saw it as an infringement on the First Amendment.

While sharp rhetoric dominated the deliberations on the House floor, both sides engaged in furious back-room lobbying aimed at tilting what could be extremely close votes today on the gun measures. President Clinton even weighed in from Switzerland with a letter to lawmakers, urging members to "stand up to the gun lobby once again."

When the Senate approved its version of juvenile justice legislation last month, it also included a three-day waiting period for sellers to conduct background checks on people buying weapons at gun shows, as well as several other gun-related measures.

But House conservatives last night appeared close to achieving a compromise on a watered-down version of the Senate-passed gun control measure -- but one being offered by a leading Democrat. The amendment being pushed by Rep. John D. Dingell (D-Mich.), a close ally of the National Rifle Association, would limit the background checks to 24 hours.

The Dingell amendment was getting a big push from Majority Whip Tom DeLay (R-Tex.), one of the most powerful House members, who urged conservatives to back the plan as their best chance of stopping tougher gun control measures.

For instance, Hyde is backing a competing approach that would set a 72-hour waiting period for gun shows featuring 10 or more vendors, while Rep. Carolyn McCarthy (D-N.Y.) is promoting a longer waiting period of three business days for any event where 50 or more guns are sold.

"It's a dilemma," DeLay told reporters. "You hate to vote for any gun control if you're a defender of the Second Amendment. At the same time, what do you do to stop the gun control people?"

It was a day of big emotions as the House began marching through 44 amendments to the juvenile offenders bill. The bill would provide extra money for states to build or expand juvenile facilities, hire prosecutors and establish programs for law enforcement training. Democrats said they have no problem with the bill, but blamed Republicans for offering a series of "poison pill" amendments that they described as off the chart.

The amendments ranged from creating a national file of violent juveniles and tougher penalties for those who commit violent acts against children to more controversial measures promoting prayer in school, posting the Ten Commandments and providing limited civil litigation immunity for teachers and principals trying to maintain discipline.

House Speaker J. Dennis Hastert (R-Ill.), a former schoolteacher and coach, told members he had been "horrified" by the shootings in Littleton and shared in Americans' confusion over how it happened and what could be done to prevent future tragedies.

"In this debate we attempt to provide answers to both these questions," Hastert said. "But let's not kid ourselves. Congress cannot quickly and easily provide complete answers that will solve the complex problem of juvenile violence. We can only try to highlight some issues that we as a society should work to solve."

Rep. John Conyers Jr. (Mich.), ranking Democrat on the Judiciary Committee, complained that the Republicans were attempting to load up the bill with amendments that might score political points with their constituents but would do little to combat juvenile violence.

"What's really extraordinary about these proposals is how meaningless they are," he said. "They are a transparent attempt to legislate by sound bite."

Conyers led a spirited Democratic fight against McCollum's amendment to toughen criminal penalties for juveniles, warning that a push to increase juvenile incarceration will only lead to a higher rate of recidivism and increased incidents of suicide and sexual assaults among juvenile prisoners.

"There are some adults who have a long pattern of violence, and maybe you can give up on their rehabilitation, but I certainly hope we don't get to the point where we give up on a 13-year-old," said Rep. Melvin Watt (D-N.C.).

However, McCollum's get-tough approach proved to have broad appeal on both sides of the aisle. Sixty-three Democrats joined with 186 Republicans in supporting McCollum's measure. "We have to send a message: If you intend to harm our children, we will punish you and punish you severely," McCollum said.

Clearly the most controversial measure debated yesterday was Hyde's amendment to crack down on the sale or rental of graphically violent films and video games to young people. The Judiciary Committee chairman argued that merely changing gun laws was not enough and that Congress had to begin to address some of the root causes of teenage violence, including the entertainment industry's obsession with violence and sex.

But opponents from both parties warned that his plan would trample on First Amendment rights and, in practice, would be a "nightmare" to enforce. Rep. Maxine Waters (D-Calif.), a Judiciary Committee member, said she was dismayed that Hyde, "one of the greatest legal minds" in Congress, "would bring this trash to the floor."

In the end, Hyde's measure attracted an extraordinary array of opponents, from liberal Democrats and libertarian Republicans concerned about First Amendment rights to Republicans from the East and West coasts who represent the politically potent movie and entertainment industries.

In the Maryland delegation, GOP Reps. Robert L. Ehrlich Jr. and Constance A. Morella, along with all four Democrats, voted against the Hyde measure, while Reps. Roscoe G. Bartlett and Wayne T. Gilchrest voted in favor of it.

The Virginia delegation was more split, with Republican Reps. Thomas J. Bliley Jr., Robert W. Goodlatte and Frank R. Wolf supporting the measure, and Democratic Rep. Virgil H. Goode Jr. joining them. GOP Reps. Herbert H. Bateman and Thomas M. Davis III and Democratic Reps. Rick Boucher, James P. Moran Jr., Owen B. Pickett, Robert C. "Bobby" Scott and Norman Sisisky all opposed the measure.

The House also adopted, by voice vote, a proposal for mandatory life imprisonment for anyone convicted of a second sex offense against a child.

Members later began considering amendments on religion, accepting 300 to 127 a measure to permit religious expression during memorial services on a public school campus.