Story highlights A bump stock is a device that enables semi-automatic rifles to fire rapidly like automatic weapons

Conway also blamed Democrats for not talking about guns before tragedies

Washington (CNN) White House counselor Kellyanne Conway blamed the Bureau of Alcohol, Tobacco, Firearms and Explosives under the Obama administration Thursday for not regulating bump fire stocks, also known as bump stocks, though it's not clear the bureau had the authority to do so.

A bump stock is a device that enables semi-automatic rifles to fire rapidly like automatic weapons. Jill Snyder, special agent in charge of the ATF, said Tuesday that the gunman in Las Vegas rigged 12 semi-automatic rifles with bump stocks.

"I did note ... it was President Obama's ATF, the Bureau of Alcohol, Tobacco and Firearms, in 2010 that decided not to regulate this device," she told CNN's Chris Cuomo on "New Day." "That should be part of the conversation and part of the facts that you put before your viewers."

In 2010, Texas-based Slide Fire pitched the device to federal regulators as a new way to assist people with disabilities to "bump fire" from an AR-15-type rifle . Breitbart News, led by former White House chief strategist Steve Bannon, noted Wednesday that the device was approved by Obama's ATF.

Because a bump stock is not a firearm, the ATF classified it as firearm part -- so the ATF wrote in a letter that it approved it because it doesn't have any real jurisdiction over firearm parts.

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