TMZ.com said the recording artist, whose real name is Clifford Harris, also pleaded guilty to possession of a firearm by a convicted felon.
He will begin a one-year prison sentence after he finishes 1,000 hours of community service, the report said.
The recording artist was arrested last October for allegedly accepting three machine guns and two silencers.
A bodyguard for Harris provided information leading to the arrest in a sting operation, authorities said.
Bureau of Alcohol, Tobacco, Firearms and Explosives agents alleged they found three other guns in the vehicle Harris was driving, including a loaded weapon under the driver's seat.
A search warrant for Harris's home in College Park, Ga., allegedly yielded six more weapons, five of which were loaded.
Harris initially pleaded innocent to the charges and was placed under house arrest while he awaited trial.
However, TMZ.com said he entered his guilty plea Thursday.