Shooter may have increased rate of fire with common devices

Video indicates possibility of ‘trigger crank’

The speed, pattern and inconsistent rate of gunfire heard in videos of the Las Vegas shooting indicate the suspect could have used cheap and legal modification devices to accelerate the firing of a semiautomatic weapon to almost 700 rounds a minute.

The kinds of devices that would make that possible are readily available on the Internet — even to people who can’t qualify to buy an automatic weapon.

Video taken near the Mandalay Bay Resort and Casino by a bystander provides audio of the continuous fire. Though fast, it’s not a consistent, fully automatic rate, said Mel Bernstein, owner of Dragonman’s shooting range in Colorado Springs, who analyzed the sounds from the video. USA TODAY counted more than 10 shots fired per second.

Semiautomatic weapons fire one round per trigger pull, and fully automatic rifles fire continuously when the trigger is depressed. It’s possible the shooter had fully automatic weapons, which are legal only with a special permit that requires fingerprinting and federal approval.

Two legal, off-the-shelf devices could have been used to achieve a fully automatic rate of fire, increasing the speed by hundreds of rounds per minute.

One, known as a “trigger crank” or “gat crank” bolts onto the trigger guard of a semi- automatic rifle. The shooter rotates the crank, which usually depresses the trigger three times per rotation, Bernstein said.

The trigger crank sells online for $40-$50 and can be purchased by mail.

“They really shouldn’t be legal — anybody with an AR-15 can bolt one on and crank out rounds as fast as a fully automatic without a class III machine gun license,” Bernstein said.

Another modification to a semiautomatic weapon that could have been used is what’s called a “bump stock.” The device modifies the stock of the gun, so the recoil helps fire rounds in rapid succession.

The shooter could have

“They really shouldn’t be legal — anybody with an AR-15 can bolt one on and crank out rounds as fast as a fully automatic.”

Mel Bernstein,

Dragonman’s shooting range

used semiautomatic weapons with legal modifications or a fully automatic weapon with or without a permit, said Mike McLively, an attorney at the Law Center to Prevent Gun Violence.

“The only issue with the modifications is you lose accuracy, but of course, if you’re aiming at tens of thousands of people in a crowd, accuracy doesn’t matter as much,” McLively said. “If it turns out a modification was used, I think it’ll start a conversation about whether they should be legal.”

Clark County Sheriff Joe Lombardo said Monday that at least one of the weapons was modified and that police were testing the rifles.