The Las Vegas shooter killed dozens and injured hundreds within an hour. A South Florida gun shop owner explains how he may have modified two firearms, which could offer insight into the gunman's monstrous rampage.
Stephen Paddock shot from his hotel room on the 32nd floor of the Mandalay Bay in Las Vegas at concertgoers hundreds of yards away, police said.
As the gunshots rained down, many perceived the sounds they heard to be automatic machine-gun fire. Out of the 23 firearms found in Paddock's room, two were assault rifles modified with a bump stock – an attachment that uses the recoil of a semi-automatic firearm to fire bullets successively, similar to a fully automatic firearm.
"It replaces the pistol grip and the stock," Caleb Giddings, owner of National Armory in Pompano Beach, said. "Lay your finger on the trigger guard over the trigger and as the stock slides back and forth on the gas tube, it bumps your finger into the trigger simulating fully automatic fire."
Giddings said the bump stock is legal and approved by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives.
While a semi-automatic rifle, such as the AR-15, will shoot one round each time you pull the trigger, a bump stock will allow the firearm to continue discharging from 400 rounds to 800 rounds a minute.
Giddings said he has heard the sounds of machine guns throughout his career, adding that just hearing the sounds of gunfire during the Las Vegas massacre is not enough to determine what sort of weapons Paddock used or modified.
"That tells me absolutely nothing," Giddings said. "It's very difficult to determine what kind of weapon is being used from echoey automatic weapon fire in an urban environment. And I think a lot of people are making assumptions based on poor information."