The Iowa man arrested outside the White House last week after the Secret Service found a gun in his car pleaded guilty Monday to reduced charges.
R.J. "Renae" Kapheim, of Davenport, Iowa, pleaded guilty in Superior Court in Washington to misdemeanor charges of possessing an unregistered firearm and unlawfully possessing ammunition. Each carries a maximum of a year in jail.
Kapheim has been in custody since he was arrested by the Secret Service on Wednesday.
Prosecutors say he told officers that he drove from Iowa in response to a phone call from President Barack Obama and that he had an appointment. When his 2013 Volkswagen Passat was searched, a .30-30 rifle, knives and at least 40 rounds of ammunition were found.
Kapheim will be held without bond until sentencing Jan. 26.