A week after the Orlando terror massacre, U.S. lawmakers will bring a set of dueling gun control measures to the Senate floor Monday — and all are expected to fail.

The scheduled votes on four separate bills address changes to the background check system as well as restrictions on gun sales for those on terror watch lists, among other areas.

The votes come after Sen. Chris Murphy, D-Conn., filibustered for almost 15 hours last week seeking action in response to the killing of 49 people in the gay nightclub Pulse by Omar Mateen, a Florida man who pledged his loyalty to ISIS in the midst of the rampage.

But since lawmakers were unable to come together on a piece of compromise legislation, the individual bills face long odds. Democrats are expected to block two Republican amendments, arguing that they fall short in controlling the sales of firearms. In turn, Republicans are certain to block two Democratic amendments, contending they threaten the constitutional rights of gun owners.

Murphy said on ABC’s “The Week” that the passage of the measures was unlikely and focused on the response to the filibuster.

"It wasn't just that 40 senators came to the floor and supported my effort to get these votes but there were millions of people all across the country who rose up and who joined our effort," he said.

The Senate will vote on a measure by Murphy to expand gun background checks and one by Sen. Dianne Feinstein, D-Calif., to keep people on a government terrorism watch list or other suspected terrorists from buying guns. The Justice Department has endorsed her legislation.

Countering that proposal, Republican Sen. John Cornyn of Texas is pushing a measure that would allow the government to delay a gun sale to a suspected terrorist for 72 hours, but require prosecutors to go to court to show probable cause to block the sale permanently. The National Rifle Association backs the legislation, but gun control advocates and Democrats say the bar is too high. 

A separate measure from Judiciary Committee Chairman Charles Grassley would boost funds for the National Instant Criminal Background Check System and ensure the correct records are uploaded into the system in a timely manner. It would also clarify language surrounding mental health issues to disqualify someone from buying a gun. Democrats say language in the bill would actually roll back some current protections.

Attorney General Loretta Lynch told “Fox News Sunday” that she also supported Cornyn’s proposal. Lynch said such an amendment would give the federal government the ability to stop a sale to somebody on the terror watch list.

However, she argued the federal government needs flexibility and the authority to protect the classified information used in denying a sale, if potential buyers exercise the constitutional rights to file an appeal.

“The American people deserve for us to take the greatest amount of time,” Lynch said.

The Pulse Orlando nightclub shooter was added to a government watch list of individuals known or suspected of being involved in terrorist activities in 2013, when he was investigated for inflammatory statements to co-workers. But he was pulled from that database when that investigation was closed 10 months later.

Both the Feinstein and Cornyn amendments would try to ensure that individuals like Mateen who had been a subject of a terrorism investigation within the last five years are flagged. Grassley's would require that law enforcement be notified if a person had been investigated in the last five years and attempted to purchase a gun.

Last week, presumptive GOP presidential nominee Donald Trump tweeted that he would meet with the NRA about "not allowing people on the terrorist watch list, or the no fly list, to buy guns." Exactly what he would support was unclear.

Separately, moderate Republican Sen. Susan Collins of Maine is working with other Republicans, as well as talking to Democrats, on a bill that would prevent people on the no-fly list — a smaller universe than targeted by Democrats — from getting guns. But her bill had not been blessed by GOP leaders and it was unclear if it would get a vote.

In the GOP-controlled House, Republicans had no plans to act on guns and Democrats were unable to force any action, given House rules less favorable to the minority party than in the Senate. 

On another front in the gun debate – concerning another mass shooting tragedy – a judge in Connecticut will hear arguments Monday on whether to dismiss a lawsuit against the maker of the semiautomatic rifle used to kill 20 children and six adults in the 2012 Sandy Hook Elementary School massacre.

The families of nine children and adults killed at the Newtown school and a teacher who survived are suing Remington Arms, the Madison, North Carolina-based parent company of Bushmaster Firearms, which made the XM15-E2S rifle used in the shooting. They say the company knew its AR-15-style rifle was meant for the military and was too dangerous to sell to civilians.

Lawyers for Remington continue to argue the lawsuit is barred by a 2005 federal law, the Protection of Lawful Commerce in Arms Act, which shields gun manufacturers from most lawsuits over criminal use of their products.

The Associated Press contributed to this report.