The powerful National Rifle Association (NRA) has appealed to US regulators to consider "additional regulations" on the rapid-fire device used by the Las Vegas gunman.
The NRA says the use of 'bump-stocks' needs to be reconsidered and said in a statement: "Devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations."
After years of resisting gun controls, Republicans said they would look at banning the tool and lawmakers will hold hearings to discuss a bill on their use.
A bill to ban bump-stocks was submitted to the US Senate on Wednesday (4 October) by California Democrat Dianne Feinstein and there may be a Republican-led version of the bill may be submitted for debate by next Thursday (12 October).
Meanwhile the authorities in Las Vegas have clashed over whether Stephen Paddock acted alone in carrying out the massacre that left 59 dead and hundreds injured amid some suggestions that he may have had outside help.
Aaron Rouse who runs the Las Vegas division of the FBI said: "Theories are great and everyone can have a theory.
Paddock's girlfriend Marilou Danley said her partner was a "kind, caring, quiet man" in a statement released through her lawyer.
She said: "I loved him and hoped for a quiet future together with him. He never said anything to me or took any action that I was aware of, that I understood in any way to be a warning that something horrible like this was going to happen."