The inmates were convicted of gun possession by a convicted felon, USA Today reported. But an appellate panel determined some had not committed a federal crime and others received excessive sentences.
Federal prosecutors in one district in North Carolina did a case-by-case review and found 175 inmates apparently eligible for release or shorter sentences.
Under the federal law, convicts can be barred from gun ownership if they were found guilty of a crime with a sentence of a year or more. But in North Carolina, sentences for some crimes depend on the previous criminal record of the defendant.
The federal courts in North Carolina interpreted the law to mean everyone convicted of a crime for which some defendants could be sentenced to at least a year was barred from gun ownership. But an appeals court ruled only those who actually received the longer sentences should be ineligible to own guns.
USA Today reported last summer its own investigation had found the Justice Department had done little to notify inmates they might be eligible for release. That story sparked the review by the office of U.S. Attorney Ripley Rand in Greensboro.
2014: The Year in Music [PHOTOS]