Questions about the "bump stock" devices used in the Las Vegas shooting massacre on Oct. 1 start with what they actually do.

Did they help Stephen Paddock shoot more people? Did they stop him from killing more?

This AR-15 rifle is fitted with a "bump stock." The stock uses the recoil of the semi-automatic rifle to let the finger "bump" the trigger, making it different from a fully automatic machine gun.

David Beaty, owner of Sun Devil Manufacturing in Mesa, Arizona, showed an Arizona Republic reporter and videographer what exactly the bump provides to the operator of a semi-automatic rifle.

His company makes aluminum rifle parts and accessories.

Semi-automatic vs. semi with 'bump stock'

This AR-15 rifle is fitted with a "bump stock." The stock uses the recoil of the semi-automatic rifle to let the finger "bump" the trigger, making it different from a fully automatic machine gun.

Beaty demonstrated three weapons at an outdoor range in the southeast Valley, wearing earmuffs and protective goggles.

He first shot the semi-automatic rifle without activating the "bump." Standing next to him, I was jolted a little.

When he engaged the bump stock for the first time, my mind blanked and my body shook. Even after he stopped shooting, I was stunned for about 30 seconds.

The same feeling returned when Beaty fired a full-automatic machine gun.

Sherri Camperchioli and Jordan Cassel, volunteers from Las Vegas, staple photos of the mass shooting victims on 58 crosses artist Greg Zanis of Aurora, Illinois, constructed. He drove across the country, arriving in Las Vegas Thursday afternoon, Oct. 5, 2017, to install them on Las Vegas Blvd to honor the people killed in the mass shooting. Zanis said he has created crosses for many of the recent national tragedies, Newtown, San Bernardino and now Las Vegas. Mandalay Bay is in the background.
Tom Tingle/The Republic

'Bump stock' easy to learn

The bump stock replaces the original stock that comes with the weapon. Anyone can buy a bump stock because it's not considered a firearm.

Beatty said he has known people who can take the bump-stock attachment out of the box and know exactly how to use it, while others have to practice multiple times.

"It's pretty easy to learn; it just helps if you know the theory behind it," Beatty said.

He said his demonstration was the first time he's ever used a "bump stock" as it came straight out of the box.

It took no more than five minutes for him to teach himself.

"It's like turning your rifle into a dragster," he said. "It's addictive; there's something addictive about shooting machine guns."

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The bump stock makes it easier to enjoy the feel of a machine gun, he said, and you don't have to pay the hefty tax toward being able to legally own a full-automatic gun.

Hitting a target is a lot easier with a full-automatic than a semi-automatic rifle with a bump stock, which is less accurate because of the jolt it gives off.

But a person is still able to hit a target, Beaty showed The Republic.

Automatic weapons costly, difficult to obtain

Beaty also demonstrated how a fully automatic gun works. The rapid fire was similar to the way a semi-automatic rifle with the bump stock worked, but the differences were notable.

Pulling the trigger on an automatic weapon will run the ammunition automatically. The shooter is still manually pulling a trigger with a bump stock, Beaty said. 

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It requires a lot of paperwork to get a fully automatic weapon, Beatty said. A law-abiding person needs to submit fingerprint cards, photo IDs, undergo a background check and pay a $200 tax.

He said the weapon itself costs quite a bit because limited numbers are available. The only automatics available to the public are those that were in circulation before a 1986 ban. The cheapest gun would run about $5,000, he said.

"We can manufacture, but we can only transfer them to military and law-enforcement agencies," Beaty said.

Increased interest in the devices

A bump stock isn't typically sought after by a hunter or for protection. Most people buying bump-stock devices are recreational users, according to Beaty.

"They are just going out to have fun," he said. "It just costs them a little more out of pocket because they are going to shoot ammo a lot faster."

Beaty owns about 10 himself, he said. He said he bought them directly from manufacturer Slide Fire when they were first introduced because it was a popular item. However, he hasn't sold any because there hadn't been a demand until now.

He posted an advertisement for a bump stock on Backpage.com, asking for $500, as an experiment. He said he was scared to check his email Friday because it didn't take more than five minutes after he posted the ad before someone asked him about it.

Beaty said he may sell a couple bump stocks but hadn't as of Friday. He said the typical price for one is between $250 and $350, so he wouldn't sell the device for his experimental price. The ad was just that, an attempt to gauge the interest of the market, he said.

The bump stock and Oct. 1

Beaty said if Paddock had known what he was doing, he could have inflicted aS much or more damage in Las Vegas with his semi-automatic rifle without the bump stock.

The bump stock isn't necessarily what contributed to the high number of people injured and killed, he said.

"It was the whole situation," Beaty said. "You pack that many people into a venue like that — for him, it was like shooting fish in a barrel."

Asked if the shooting was preventable, Beaty said that, given the circumstances, he doesn't believe it was.

Beaty said most people are responsible with their firearms. Many enjoy working on the weapons and learning how to use them better, he said.

"It's like a guy and his car," he said. "You got a guy who tinkers with his car, and he's always trying to do something new with it to make it better. It's just a different activity."

If a law is passed to outlaw bump stocks, the only people affected are law-abiding citizens, Beaty said, because criminals wouldn't abide by such a law.