Yielding to intense and growing public pressure in the wake of the Las Vegas massacre, some congressional Republicans and the White House are cautiously signaling support for a ban on bump stocks, the add-ons that can transform a semi-automatic weapon into a virtual machine gun.

Banning the devices would be a small — but important — development that could break years of gridlock and perhaps create a path forward for this nation to come together on ways to deal with growing gun violence.

A week ago, most Americans didn't know bump stocks existed. That changed when law enforcement officials found that Stephen Paddock had outfitted a dozen semi-automatic weapons with the devices, allowing him to unleash a cascade of gunfire that took 58 lives and injured nearly 500 concertgoers in a matter of minutes. Typically, only automatic weapons — still tightly regulated in the U.S. — would be capable of such high-speed destruction.

But about a decade ago, a cheap workaround to those federal restrictions hit the market. Bump stocks are unregulated, aftermarket devices that harness a semi-automatic's natural recoil to "bump" the trigger repeatedly, allowing a near-continuous stream of gunfire. What the weapon loses in accuracy, it gains in sheer volume, firing, according to some claims, 100 rounds of ammunition in as little as seven seconds.

Incredibly, the Bureau of Alcohol, Tobacco and Firearms under President Barack Obama signed off on the devices in 2010, declaring them to be firearms parts not subject to regulation. The cheapest bump stocks now sell for as little as $100. Sellers knew the right button to push, with lures like this: "Want a machine gun but can't afford the $20k buy-in? A bumpfire stock is just the ticket to getting the fun out of your AR-15 without breaking the law!" In a horrifying development, the Las Vegas attack set off a wave of demand, leaving manufacturers temporarily out of stock.

Sensing vulnerability on this issue, the National Rifle Association's CEO, Wayne La Pierre, on Thursday finally allowed that bump stocks "should be subject to additional regulations." But he's wrong. They should be banned, period. They serve no purpose for hunters and are banned as unsafe on many ranges — including the NRA's own.

Even some gun rights stalwarts in Minnesota's congressional delegation are coming around. Rep. Tim Walz said he would back a ban on bump stocks, as did Democratic Rep. Collin Peterson, through a spokesman. Republican Rep. Erik Paulsen, also through a spokesman, said that "banning bump stocks is reasonable and responsible. Automatic weapons are already illegal, and a device that effectively converts a firearm to an automatic weapon should also be outlawed." He also is asking ATF to re-evaluate bump stocks.

Regrettably, Republican Rep. Tom Emmer did not provide a comment and Rep. Jason Lewis did not respond to requests for comment. They have a responsibility to let Minnesotans know where they stand and why.

Americans who want the killing to stop should also keep the pressure on Congress. There's finally evidence that, despite all the naysayers, some progress on gun laws may be in sight.