The US National Rifle Association says devices that allow semi-automatic rifles to function like fully automatic ones need tougher regulation.
On Thursday the powerful gun lobby called on regulators to determine whether the bump-stock devices comply with federal law.
A shooting rampage on Sunday night in Las Vegas killed 58 people and wounded nearly 500, the most deadly mass shooting in modern US history and has reignited debate around regulation of firearms.
- Las Vegas shooting: Police assume Paddock 'had some help'
- Who was Las Vegas shooter Stephen Paddock?
- Las Vegas gunman planned to escape - officials
- Las Vegas shooting act of 'pure evil' - Trump
Officials said 12 of the rifles authorities recovered from a hotel suite in Las Vegas used by gunman Stephen Paddock were fitted with bump stocks, allowing the guns to be fired almost as though they were automatic weapons.
"The National Rifle Association is calling on the Bureau of Alcohol, Tobacco, Firearms and Explosives to immediately review whether these devices comply with federal law," it said in a statement.
"The NRA believes that devices designed to allow semi-automatic rifles to function like fully automatic rifles should be subject to additional regulations," it said.
It comes as the White House welcomed efforts by both political parties to address the use of bump stocks, following the Las Vegas mass shooting.
"We know that members of both parties and multiple organisations are planning to take a look at bump stocks and related devices," White House spokeswoman Sarah Sanders told reporters.
"We certainly welcome that and would like to be part of that conversation," Ms Sanders said.
Earlier US House Speaker Paul Ryan said US lawmakers need to examine "bump stock".
"Clearly that's something we need to look into," Mr Ryan told a radio talk show on Thursday, adding many lawmakers had not been aware until now such devices, which enable guns to be turned into rapid-fire weapons, existed.
Justice Department officials said it was stepping up efforts to trace guns used in violent crime.
Normally it can take the Bureau of Alcohol, Tobacco, Firearms and Explosives five to six days to trace a gun used in a crime back to the original buyer, a Justice Department official said.