The National Rifle Association has said the device used to modify the Las Vegas gunman’s weapons should be subject to more regulation.
Stephen Paddock had used “bump stocks” to transform his semi-automatic rifles into fully automated guns, capable of catastrophic damage.
The massacre, in which 58 people died and about 500 were injured, reheated the debate over America’s gun laws.
The NRA has come in for intense criticism for its pro-weapons stance.
But in a statement, it has said: “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.”
The gun lobby added: “The NRA believes that devices designed to allow semi-automatic rifles to function like fully automatic rifles should be subject to additional regulations.”