In this Oct. 4, 2017 file photo, a device called a “bump stock” is attached to a semi-automatic rifle at the Gun Vault store and shooting range in South Jordan, Utah. The Trump administration is moving to officially ban bump stocks, which allow semi-automatic weapons to fire rapidly like automatic firearms. A senior Justice Department official said Tuesday bump stocks will be banned under the federal law that prohibits machine guns. It will take effect in late March. (AP Photo/Rick Bowmer)