This is taken straight from the instruction section of the ATF form 4473 which is part of the checks system when purchasing anybfirearm: Question 11.b. - 11.l. Definition of Prohibited Person: Generally, 18 U.S.C. § 922 prohibits the shipment, transportation, receipt, or possession in or affecting interstate commerce of a firearm by one who: has been convicted of a misdemeanor crime of domestic violence; has been convicted of a felony, or any other crime, punishable by imprisonment for a term exceeding one year (this does not include State misdemeanors punishable by imprisonment of two years or less); is a fugitive from justice; is an unlawful user of, or addicted to, marijuana or any depressant, stimulant, or narcotic drug, or any other controlled substance; has been adjudicated mentally defective or has been committed to a mental institution; has been discharged from the Armed Forces under dishonorable conditions; has renounced his or her U.S. citizenship; is an alien illegally in the United States or an alien admitted to the United States under a nonimmigrant visa; or is subject to certain restraining orders. Furthermore, section 922 prohibits the shipment, transportation, or receipt in or affecting interstate commerce of a firearm by one who is under indictment or information for a felony, or any other crime, punishable by imprisonment for a term exceeding one year.
Question 11.b. Under Indictment or Information or Convicted in any Court: An indictment, information, or conviction in any Federal, State, or local court. An information is a formal accusation of a crime verified by a prosecutor.
EXCEPTION to 11.c. and 11.i.: A person who has been convicted of a felony, or any other crime, for which the judge could have imprisoned the person for more than one year, or who has been convicted of a misdemeanor crime of domestic violence, is not prohibited from purchasing, receiving, or possessing a firearm if: (1) under the law of the jurisdiction where the conviction occurred, the person has been pardoned, the conviction has been expunged or set aside, or the person has had their civil rights (the right to vote, sit on a jury, and hold public office) taken away and later restored AND (2) the person is not prohibited by the law of the jurisdiction where the conviction occurred from receiving or possessing firearms. Persons subject to this exception should answer “no” to 11.c. or 11.i., as applicable.