Republicans seem to be humoring a gun control proposal to ban “bump stocks” — a device the Las Vegas shooter likely used to make his semiautomatic weapon function as a fully automatic one.

In the wake of the tragic mass shooting in Las Vegas, which left 59 dead and injured hundreds more, Democrats and Republicans in both the House and Senate have proposed banning bump stocks. Police found 12 bump stock devices in the hotel room the Nevada gunman shot from, an explanation for the rapid gunfire at the incident.

If the Republican-led Congress does decide to implement some kind of gun reform in response to the shooting — considered the deadliest in modern US history — this narrow restriction of bump stock sales appears to be the best bet.

The push has come from Democrats, like Dianne Feinstein (D-CA) in the Senate and in the House, a bipartisan effort from Carlos Curbelo (R-FL) and Seth Moulton (D-MA), but Republicans at large have signaled they are open to similar legislation.

“Fully automatic weapons have been banned for a long time,” House Speaker Paul Ryan said. “Apparently this allows you to take a semiautomatic and turn it into a fully automatic, so clearly that's something we need to look into."

But there are already signs that this push could be all talk. The National Rifle Association, which orginally said bump stocks should be “subject to additional regulations,” is now saying any action should come from the Trump administration — not from Congress — a distinction that will likely muddy hopes of any action on Capitol Hill.

With each mass shooting, Congress reignites a longstanding debate on gun control. But it’s largely one that fizzles out in time, resulting in little to no legislative changes. This time Democrats might have found the narrowest version of gun control legislation that could conceivably bring Republicans on board. If this doesn’t work, it shows just how unlikely any gun reform legislation is under a Republican-led Congress.

Republicans are showing interest. It could just be talk.

Already top congressional Republicans have expressed interest in at least considering the ban — which is more attention than most gun control proposals get from the GOP.

Majority Whip Sen. John Cornyn said it would be “worthwhile” to have a hearing on the legislation, saying the devices are “certainly something that’s got my attention and I think we ought to get to the bottom of it.” The third-ranking Republican senator, North Dakota’s John Thune, also said “it’s something we ought to look into.”

“It looks to me that these kits that turn these things into automatic weapons is a place you could really get some bipartisan support,” Oklahoma Rep. Tom Cole, a top Republican in the House, told Vox.

Even some of the most conservative Congress members have said it’s something they could consider. Rep. Joe Barton (R-TX), who said there is little wiggle room in the Second Amendment, said he’d look at a bump stock ban, and Rep. Mark Meadows (R-NC), who chairs the ultraconservative House Freedom Caucus, said he could be for it.

On its own, the bump stock ban seems narrow enough that Republicans can explain supporting it: Automatic weapons are mostly banned in the United States, and this device is essentially a loophole to that regulation.

“The only reason you would need that kind of capability I believe is to kill a lot of people very fast,” Rep. Tom Rooney (R-FL) said on CNN. “And so, when somebody tries to equate that to me holding a handgun when I'm driving to the movies or to a mall with my kids for protection, I just don't buy it. I'm not buying it.”

But public support for this kind of legislation spikes in the immediate aftermath of a mass shooting — an energy that eventually fizzles out in the following months, making an already low-priority issue for Republican members even less pressing.

And already many top Republicans, including Thune and Cornyn, are saying they need to know more. The line from congressional Republicans is that despite most of them being gun owners, they had never heard of bump stocks before the Las Vegas shooting. House Majority Whip Rep. Steve Scalise (R-LA), who just returned to Congress after being critically injured at a mass shooting targeting congressional Republicans in the summer, poured some cold water on the energy behind the effort.

“I do think it's a little bit early for people to say they know what to do to fix this problem,” he told NBC News’s Meet the Press with Chuck Todd. “If you talk to anybody about a week ago, most people, including myself, didn’t even know what a bump stock was.”

“There are people that want to rush to judgment,” he continued. “They've got a bill written already.”

To be clear, Feinstein, who is sponsoring the Senate bill, had raised the issue of bump stocks in 2013 — to no avail.

We’ve been here before

Despite Republicans pleading ignorance, this isn’t the first time a ban on bump stocks has been brought up in Congress.

Feinstein had raised concern about bump stocks in Congress, bringing up a similar but more sweeping restriction in 2013 that proposed banning all semiautomatic weapons that could accept a “military feature” like a detachable stock. At the time, the bill faced fierce opposition even among Democratic senators, including West Virginia’s Joe Manchin.

Now, as awareness around mass shootings and gun violence rises again, Feinstein’s proposed ban is much narrower: on the bump stocks themselves. It’s already seen some opposition from gun lobby groups like Gun Owners of America, which said bump stocks should be available “to help gun owners with disabilities fire their weapons.”

The NRA originally seemed more open. But they drew an important line: They don’t want this restriction written into law.

“The NRA believes that devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations,” the organization said in a statement. But in a twist, it called on Trump’s administration — the Bureau of Alcohol, Tobacco, Firearms, and Explosives — to review a ban on the devices.

In other words, the NRA is suggesting taking the matter out of Congress’s hands. But in the past, ATF has said it does not have purview over attachable devices like bump stocks — calling on Congress to authorize any kind of ban.

“If we could legislate morality, we would have done it long ago,” Wayne LaPierre, NRA executive, said on CBS’s “Face the Nation” on Sunday, repeating a now time-old excuse from Republicans, that there’s nothing Congress can actually do on gun laws to stop mass shootings.

This kind of confusion could lead to more delays and ultimately allow the gun control debate to fizzle out, as it has many times in the past.

“I am sure there will be some debate on it, and then we will go down the road and something else will happen and it will get in the background again,” Rep. Roger Williams (R-TX) said on whether Congress would actually address gun laws.