How did the shooter get such a large arsenal? Easily and legally

WASHINGTON: Forty-seven firearms from three locations. Piles of ammunition, and devices that converted assault rifles to automatic weapons that fired like machine guns.

How did Las Vegas gunman Stephen Paddock amass an arsenal of firearms? In the US, and in Nevada, it’s easy. And legal.

Although the country is notorious for its lax gun laws, there are some restrictions on multiple sales of handguns. But if someone wants to build up a cache of rifles the way Paddock did, they could do so without anyone noticing.

Most gun sales are by federally licensed vendors who must put buyers through background checks. The FBI will run their name through the National Instant Criminal Background Check System, which refers to three databases of offenders.

Those databases are not always perfect, relying on often spotty reporting from the states.

But if a person’s record is clean — and Paddock evidently did not raise any red flags — he can buy as many guns as he wants.

What stood out in Sunday’s massacre was the rapid pace of fire. According to reports, Paddock modified some of his guns to work like automatic weapons, able to shoot hundreds of rounds a minute with one trigger pull.

Automatic weapons are banned in the US. But converting a semi-automatic weapon, including the AR-15 and Ak-47type assault rifles, into an automatic weapon is easy.

For $40 you can buy a trigger crank,which can make the gun fire three or four times with each turn of the crank, significantly faster than using a finger to pull the trigger. And for as $99, you can get a bump stock, a springloaded stock that, with one pull of the trigger, keeps the weapon firing using its own recoil. It can enable the weapon to fire at a rate of 600 rounds a minute.