A federal judge has found part of Chicago’s gun law unconstitutional.

Shawn Gowder was convicted of unlawful use of a weapon in 1995 because he illegally owned a gun in Illinois under 720 ILCS 5/24-1 (a)(10). He was sentenced to 12 months probation.

The City of Chicago requires city residents to get a Chicago Firearm Permit to legally possess guns in their homes. In 2010, Gowder applied for a permit, but the city denied him. It cited the city’s firearm ordinance that says an applicant will be denied if he’s been convicted in any jurisdiction of unlawful use of a firearm.

Gowder claimed that violated his Second Amendment right. And a federal judge agreed with him.

Judge Samuel Der-Yeghiayan noted in his opinion that Gowder’s past conviction was not a violent use of a weapon, but an unlawful possession of one.

He ruled that part of the city’s ordinance is “unconstitutionally void for vagueness” because unlawful use isn’t clearly defined. He notes the phrase has different interpretations in other jurisdictions.

A spokesman for the city’s law department says it’s disappointed in the judge’s ruling and it’s reviewing next steps.