It’s a start. Some top Republicans, usually allergic to any gun control measures, signaled they could be open to banning the “bump stock” accessory used in the Las Vegas massacre. The add-on modifies a semi-automatic rifle to fire more quickly — hundreds of rounds per minute — like a fully automatic weapon. Members of both parties have either introduced, or plan to submit, bills banning the kits. Perhaps the biggest surprise, however is the National Rifle Association’s call today to further regulate bump stocks. Meanwhile, gun stores are seeing demand for the devices skyrocket.