Welcome to BrainStuff, from How Stuff Works.

Hey Brain Stuff, it's Christian Sager here.

On Sunday, October 1st, 2017,

a country music festival in Las Vegas became the scene of a mass killing

when a gunman positioned in a high-rise hotel began shooting at concert

goers. At least 58 died and more than 500 others were injured before the shooter took his own life.

This is according to Las Vegas TV Station KX&T.

During the attack, the shooter at one point managed to fire nearly 90 rounds in just 10 seconds

according to a New York Times analysis of audio posted on social media. The speed of that bullet barrage led some to assume

that the killer used a fully automatic firearm, a type of gun that

automatically reloads after a shot is fired, fires again, and then repeats the process as long as the trigger

remains depressed.

With the Firearm Owners Protection Act of 1986, Congress banned the sale of new fully automatic firearms, but ones produced

before that date are still obtainable after the purchaser goes through an FBI

background check.

But the Las Vegas killer didn't need a fully automatic weapon

to unleash rapid fire terror.

In a Wednesday October 4th press conference, Jill Snyder, special agent in charge for the Bureau of Alcohol,

Tobacco and Firearms from the San Francisco office, said that when authorities reached the

gunman's hotel room, they found an arsenal that included

12 semi-automatic rifles equipped with aftermarket attachments called bump firestocks. As Snyder explained, the devices are designed to

simulate automatic fire without mechanically altering the function of a

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