After Stephen Paddock used semiautomatic rifles with bump-stock modifications to shoot 489 people in 10 minutes in Las Vegas on Sunday night, killing at least 58 of them, several congressional Republicans said they are open to dropping their longstanding opposition to regulating firearms and considering a ban on bump stocks. Even Sen. John Cornyn (R) and other members of the Texas GOP delegation said they would consider or back regulating the once-obscure accessory, which replaces a rifle's stock with a device that allows a semiautomatic to fire like an automatic rifle. Two of the main bump-stock manufacturers are in Moran, Texas, near Abilene.

The Las Vegas shooter altered a semiautomatic rifle to fire like an automatic — and did it legally.https://t.co/J4cut8lgTg pic.twitter.com/2RRspPDZsE — Los Angeles Times (@latimes) October 4, 2017

In the meantime, they remain legal, and "it is getting increasingly harder to find one to buy," reports The Trace. "Scores of online retailers have sold out of the devices," and though Walmart and Cabela's appear to have stopped selling them online Wednesday, "business is booming" for the retailers that still have them for sale.

It's pretty common for gun sales to rise after mass shootings. After the murder of 20 young schoolchildren and six adults at Sandy Hook Elementary School in Newtown, Connecticut, the FBI processed nearly a million gun background checks in a week, The Trace notes, which is a record for any seven-day period. And as many avid gun collectors — those with eight to 140 firearms — told The Guardian in 2016, they started amassing their large arsenals almost haphazardly after the Newtown shooting, buying AR-15s because they thought they might be banned.

On Wednesday, Pennsylvania gun owner Zack Cernok told The New York Times he was buying one, even though "I don't even have the gun for it," because "for $100, it's almost not a bad investment to buy it, try it out and sell it if I don't like it." Peter Weber