Are you looking for a bump fire stock to legally convert your semi-automatic rifle into what basically functions as a fully automatic machine gun? It will probably be hard to find one in King County, even though they're apparently in high demand after a gunman used the device as he massacred 58 people and injured hundreds more at a concert in Las Vegas on Sunday.

The Las Vegas shooter had 12 rifles modified with bump stocks in his hotel room. Bump stocks replace the stock, or back of the rifle and use kickback energy from firing to move the gun back and forth and shoot quickly, similar to the speed of an automatic weapon. A shooter just needs to hold down the trigger to spray hundreds of rounds per minute. Modifying a rifle this way is perfectly legal (though that could change), even though automatic weapons like machine guns are essentially illegal.

Bump stocks are selling out quickly around the country. We called up local gun shops to see how many carry them and what the demand was.

Of the 13 that answered, most said they didn’t carry bump stocks. Sometimes this was a conscious decision. “We do not and will not,” said a woman who picked up the phone for Low Price Guns in Bellevue. Someone from Joe's Guns & Stuff in Shoreline said he didn’t sell them because he doesn’t like them—though he doesn’t think they should be banned.

Shops that do sell them said they’d gotten lots of interest from customers in the days after the Las Vegas shooting.

At one store, bump stocks sold out quickly after the shooting (mostly online). (We are declining to name stores that sell bump stocks because we don't want to give that kind of advertising.) Before the shooting, they were selling theirs at a discount for four years because no one was interested. Now, lots of people were interested who aren’t normally gun people, the employee said. The store has no plans to order more, as he thinks they will be banned, “unfortunately.”

An employee at another store said they’re usually fairly popular. Now they only have one left. The store has no plans to stop selling them unless they’re made illegal. "It's all up to the state." It would be bad for business to stop selling something just because some people don't like it, the employee said—after all, McDonald’s would never do that.

Some shops told us they didn’t sell many bump stocks because they’re a stupid and gimmicky piece of equipment. “They’re kind of hokey, honestly,” said an employee at one of the stores that sells them. “They kind of became the laughingstock of the gun world.”

Says Thor Gulsvig, manager of Pinto’s Gun Shop in Redmond: “From a standpoint of—our general cultural attitude, I can see people wanting something like that.” But, “personally I would say, there is no practical point to it....My understanding is they’re not very accurate. It’s kind of a gimmicky thing and you’re going to burn through a lot of ammo and not do any real meaningful shooting.”

According to a piece in The Trace, a nonprofit publication covering American gun violence, “Bump Fire stocks and others like them serve gun owners who shoot for thrill and status, not for any practical or sporting purpose. These stocks have lately become the most transgressive, showy gear in a market comprised almost exclusively of transgressive, showy gear.”

Of course, the shooter in Las Vegas didn’t need any great accuracy to gun down people at the concert. And gimmicky or not, there’s now a lot of momentum to ban bump stocks. On Tuesday, Governor Jay Inslee called for a state ban on bump stocks. Democrats in Congress introduced legislation to ban them yesterday (including Washington Senators Patty Murray and Maria Cantwell). Some Republicans in Congress support a ban. Even the National Rifle Association asked the Trump administration to review whether bump stocks are legal (and uh, in the process, took a shot at the Obama administration for not regulating them).

Steven Hsieh contributed reporting.