Question: are drop in auto sear legal?
Answer: Regardless of the date of manufacture of a drop in auto sear (i.e., before or after November 1, 1981) the possession or transfer of an unregistered drop in auto sear (a machinegun as defined) is prohibited by the National Firearms Act (NFA), 26 U.S.C. § 5861, and the Gun Control Act, 18 U.S.C. § 922(o).