Before 1 January 2019, will the US federal government ban the manufacture, importation, possession, or sale of bump stocks?
In the wake of the mass shooting in Parkland, Florida, President Trump signalled his willingness to regulate "bump stocks," an after-market accessory for semi-automatic rifles. (NY Times) Legislation banning such devices has been introduced in Congress (CNN, CNN), and Speaker Paul Ryan has called for the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) to ban them by regulation (The Hill) under existing law. Regulatory or legislative bans will count, as will bans with exemptions. The date that any ban would take effect is immaterial to the outcome of the question.