WASHINGTON – Congressional gun-control advocates are preparing to take another run at expanding background checks on those looking to purchase firearms.

The legislation pending in the House requires that background checks on gun purchasers be required at gun shows and in similar settings. Currently, only transactions involving federally licensed firearms dealers require a background check.

A Senate bill requiring instant background checks for almost all sales through the FBI’s National Instant Criminal Background Check System, which also prohibited firearms listings on unlicensed websites, fell six votes shy of the 60 needed to break a filibuster in April. But proponents maintain the culture is quickly changing and that support for additional firearms restrictions is growing in both the public and on Capitol Hill.

The Public Safety and Second Amendment Rights Protection Act of 2013, a measure sponsored by Rep. Peter King (R-N.Y.) and Rep. Mike Thompson (D-Calif.), who chairs the House Gun Violence Prevention Task Force, has been sitting idly in the House Subcommittee on Crime, Terrorism, Homeland Security and Investigations since April. But it has 185 co-sponsors, leaving it 33 votes short of a majority in the lower chamber. In addition to expanding background checks, the King-Thompson legislation creates a commission to study and report on the “root causes of these recurring and tragic acts of mass violence.”

“Right now, a criminal in many states can buy a firearm at a gun show, over the internet, or through a newspaper ad – because those sales don’t require a background check,” Thompson said. “Last year, the background check system identified and denied 88,000 gun sales to criminals, domestic abusers, those with dangerous mental illnesses and other prohibited purchasers. However, those same criminals could buy those same guns at a gun show or over the Internet without any questions asked. H.R. 1565 closes this huge loophole, greatly reducing the number of places a criminal can buy a gun.”

Thompson said the bill protects rights under the Second Amendment to the U.S. Constitution by providing an exemption on background checks for firearm transfers between family and friends.

“You won’t have to get a background check when you inherit the family rifle, borrow a friend’s shotgun for a hunting trip or purchase a gun from a buddy or neighbor,” Thompson said.

It further bans the creation of a federal registry and makes the misuse of records a felony, punishable by up to 15 years in prison. It allows active duty military to buy firearms in their home states and the state in which they are stationed, authorizes the use of a state concealed carry permit in lieu of a background check to purchase a firearm and allows interstate handgun sales from licensed dealers.

Sen. Chuck Schumer (D-N.Y.), who sponsored the legislation that failed to make it through the Senate earlier this year, said public outrage over mass shootings – a September incident at the Navy Yard in Washington that left 13 dead including the shooter is a recent example — and the persistent advocacy of gun-control supporters have created a political atmosphere similar to the 1990s when Congress passed the Brady Bill.

Named for James Brady, the press secretary for President Ronald Reagan who was seriously wounded during an assassination attempt outside the Washington Hilton in 1981, the Brady Bill established the five-day waiting period and background checks on about 60 percent of all handgun purchases. It became law only after a seven-year legislative battle.

“So we’re going to pass this law,” Schumer said. “We are going to finish the job and pass background checks and then move on and do other things we have to do to get guns off the streets and stop gun violence.”

But there are certainly impediments to passage. The makeup of the Senate has changed little since supporters proved unable to break the filibuster in April, leaving little reason to believe support has shifted sufficiently to push it through the upper chamber.

And while the King-Thompson bill has 185 co-sponsors, only three of them are Republicans. It does not carry the support of the GOP leadership and House Speaker John Boehner (R-Ohio) will almost certainly impose the Hastert rule – named after former House Speaker Denny Hastert, an Illinois Republican – which means the measure would have to attract the support of a majority of the GOP caucus before it can be considered.

The measure also faces strict opposition from the National Rifle Association, a powerful lobbying group. Chris Cox, executive director of the NRA, said expanding background checks, at gun shows or elsewhere, “will not reduce violent crime or keep our kids safe in their schools.”

“The NRA will continue to work with Republicans and Democrats who are committed to protecting our children in schools, prosecuting violent criminals to the fullest extent of the law and fixing our broken mental health system,” Cox said.

Nonetheless, House Democratic Leader Nancy Pelosi (Calif.) said she remains optimistic, maintaining that polls show 90 percent of the public favors expanded background checks.

“What we want is to get people to sign on, or at least say they will support the bill, and to urge the leadership of the House to take up the bill,” Pelosi said. “I believe if the bill were taken up in the House that it would pass and when it passes the House, some senators – well-intentioned – would no longer have the excuse: ‘It’s no use my risking my political career because it’s not going any place in the House.’ Let’s prove it. Let’s turn that around. Pass it in the House. Just put the pressure on to take up the bill.”

Dan Gross, president of the Brady Campaign to Prevent Gun Violence, agreed, asserting that gun-control advocates want to “finish the job.”

“Momentum is on our side,” he said. “The will of the American people will not go away. The original Brady law took six votes over seven years to pass. We hope to achieve change even sooner this time. But whatever it takes, if it does something real to prevent more people from getting shot and killed, it’s worth it.”