Ok. I had to look this up to get a better idea of what it is, but apparently, of the devices and weaponry found in possession of Stephen Paddock, the maniac who opened fire on concert goers in Las Vegas on Sunday, killing 59 and injuring over 500 others, was something called “bump-stocks.”

Some of you are probably already familiar with bump-stocks, or bump-fire systems, as I’m seeing it called. For those who are like me and have never heard the term before, this is what I found, from Bumpfiresystems.com:

Did you know that you can do simulated full-auto firing and it is absolutely legal? Bump Fire Systems is here to introduce you to Bump Fire Stock, that allows you to recreate the feeling of automatic firing. You can use it with your semiautomatic weapon by gripping the fore-end of the barrel and pulling it forward. Bump Fire uses a gun’s recoil to shoot multiple rounds.

These stocks have apparently come under scrutiny of lawmakers before, so expect there to be a new look, now.

In some of the video footage that hit social media from the chaotic scene in Las Vegas, you can hear the rapid-fire shots, and the initial belief was that he had machine guns.

For all the world, that’s what it sounded like, and then the debate over the legality of owning machine guns closely followed.

It was just part of the confusion, grief, and outrage of the day.

The Associated Press, in reporting the discovery of bump-stocks in Paddock’s hotel room, explained further how bump-stocks work.

Numerous attempts to design retrofits failed until recent years when bump stocks came on the market.

The device basically replaces the gun’s shoulder rest, with a “support step” that covers the trigger opening. By holding the pistol grip with one hand and pushing forward on the barrel with the other, the shooter’s finger comes in contact with the trigger. The recoil causes the gun to buck back and forth, “bumping” the trigger.

Technically, that means the finger is pulling the trigger for each round fired, keeping the weapon a legal semi-automatic.

Paddock was found with two bump-stocks. Authorities are still investigating to see if those stocks were used in the attacks, but given the sounds from the video, and the fact that he had them with him, I’m going to say it’s a really safe bet that they were.

If you need further illustration of what bump-stocks do, this video should do the trick.