To answer my own question from an earlier post there is no due process at this time.
On April 14, 2016 Rand Paul introduced an act,
Protecting Gun Rights and Due Process Act, to protect people from automatic placement on a NICS banned list.
https://www.paul.senate.gov/news/pre...ue-process-act
synopsis of act:
•Prohibits the sale or disposition of a firearm or ammunition to an individual that
has been adjudicated (my emphasis) as mentally incompetent or committed to a psychiatric hospital.
Adjudication requires findings by a judicial officer or court and the individual receives notice to participate with counsel (my emphasis).
•Within 90 days, the Secretary of Veterans Affairs must review and remove from NICS any veteran that has not been adjudicated as mentally incompetent. The Attorney General will certify that the removal of names has taken place.
•Prevents the Social Security Administrator from reporting individuals to NICS unless individual has been adjudicated as mentally incompetent. Attorney General will conduct a yearly review to certify reported names have necessary documentation.
•Attorney General must certify a state’s report indicating a person had been adjudicated as mentally incompetent prior to inclusion to NICS.
•All individuals considered to no longer be adjudicated as mentally incompetent will be notified and have their rights restored.