The National Rifle Association (NRA) is calling for the ATF to review "bump stock" regulations.

Meanwhile, gun stores are selling out of the device across the nation.

Officials say that's what the Las Vegas shooter used to fire hundreds of rounds into a crowd of 22,000 people.

To be clear, the ATF says stock bumps are not illegal.

The device was originally created to help people with disabilities use rifles.

Channel 3 called several local gun shops and none of them normally carry the device in store.

David Smith opened his gun shop four years ago.

This week, he says he has gotten several calls about bump stocks. However, he says the device has never been popular, until now.

“In my four years I had only sold one and that was a special order,” Smith says. “So, I never thought it would be worth it to keep one in my store."

“Now that this has come out that this guy had one and hurt some people now everybody wants one,” Smith adds.

Smith says he called his distributor to see if any bump stocks were available.

“He said we probably won't be getting any for a while until all of this blows over,” Smith says. “We just got off the phone with another distributor in Minnesota and they're out of them.”

But what does a bump stock do?

“It's just kind of like rigging your gun to shoot as fast as you can possibly shoot it,” Smith explains.

An illustration shows the stock "bump" back and forth between the shooters shoulder and trigger finger, but the rifle stays in place. That's what allows the rifle to fire rapidly. 

It's not clear if regulations surrounding bump stocks will change, but Smith says gun safety is important.

“Gun safety is a big issue here,” Smith says. “You need to always practice gun safety.”    

As far as national retailers, a Walmart spokesperson tells Channel 3, their stores do not sell bump stocks.

Channel 3 called Cabela’s in Rossville, and an employee there tells us they are sold out.

It's not clear if that's the case for other locations.