LOS ANGELES—A South Los Angeles rapper whose YouTube videos have racked up millions of views pleaded guilty April 1 to a federal charge.

Trevor Hurd, 31, known by his stage name Crip Mac, pleaded guilty in downtown Los Angeles to one federal count of being a felon in possession of ammunition. The charge carries a possible sentence of up to 10 years behind bars.

U.S. District Judge Dale S. Fischer set sentencing for July 22 in Los Angeles federal court.

Mr. Hurd was arrested in December in state court by U.S. Marshals moments after a Los Angeles County judge agreed to drop gun charges so federal prosecutors could take the case, court records show.

The indictment states that Mr. Hurd was found in September in possession of a handgun bearing no serial number—commonly known as a ghost gun—and 10 rounds of ammunition.

According to the document, Mr. Hurd has been arrested on felony charges five times since 2014 and convicted at least once. The charges include two arrests for being a felon in possession of a firearm, attempted second-degree armed robbery, grand theft, and transportation of a controlled substance, the indictment says.