Senior Republicans are open to considering legislation banning "bump stocks" like the gunman in Las Vegas apparently used to effectively convert semi-automatic rifles into fully automated weapons.
The comments from politicians including the Republican John Cornyn marked a surprising departure from his party's general antipathy to gun regulations of any kind.
However, congress was far from a guarantee of a path forward for the new legislation by senator Dianne Feinstein, especially with Majority Leader Mitch McConnell and House Speaker Paul Ryan making clear their priorities are elsewhere.
"If somebody can essentially convert a semi-automatic weapon by buying one of these and utilising it and cause the kind of mayhem and mass casualties that we saw in Las Vegas, that's something of obvious concern that we ought to explore," Mr Cornyn told reporters.
"I own a lot of guns and as a hunter and sportsman I think that's our right as Americans, but I don't understand the use of this bump stock and that's another reason to have a hearing."
Mr Cornyn later said he had spoken with Judiciary Committee Chairman Chuck Grassley, and that Mr Grassley was interested in convening a hearing.
The devices, known as "bump stocks" among other names, are legal and originally were intended to help people with limited hand mobility fire a semi-automatic without the individual trigger pulls required.
They can fit over the rear shoulder-stock assembly on an automatic rifle and, with applied pressure, cause the weapon to fire continuously increasing the rate from between 45 and 60 rounds per minute to between 400 and 800 rounds per minute, according to Ms Feinstein's office.
The government gave its seal of approval to selling the devices in 2010 after concluding that they did not violate federal law.
Meanwhile, in House of Representatives, democrats Dina Titus of Nevada and David Cicilline of Rhode Island introduced a bill to ban the manufacture, possession, transfer, sale or importation of bump stocks.
Ms Titus, whose district includes the site of Sunday night's rampage, said: "The victims and families in Las Vegas don't need an explanation about the difference between machine guns and firearms with bump stocks. They need action."
The National Rifle Association, which has played a major role in exerting political pressure against gun curbs, did not respond to inquiries about its stance on Ms Feinstein's bill.
At least one Republican senator, Ron Johnson of Wisconsin, said outright he was prepared to vote to ban "bump stocks." ''I have no problem in banning those," he said.
Senator John Thune of South Dakota, said, "I'm interested in finding out more about bump stocks and I've got my staff looking into that and I know there are other members interested in finding out more about it as well."
Speaker Paul Ryan, a republican, said: "What I don't think you want your government to do is to lurch toward reactions before even having all the facts.
"Bad people are going to do bad things."