District of Columbia Code Division IV. Criminal Law and Procedure and Prisoners. § 22-4505. Exceptions to § 22-4504.

(1) Marshals, sheriffs, prison or jail wardens, or their deputies, policemen or other duly appointed law enforcement officers, including special agents of the Office of Tax and Revenue, authorized in writing by the Deputy Chief Financial Officer for the Office of Tax and Revenue to carry a firearm while engaged in the performance of their official duties, and criminal investigators of the Office of the Inspector General, designated in writing by the Inspector General, while engaged in the performance of their official duties;

(2) Special police officers and campus police officers who carry a firearm in accordance with D.C. Official Code § 5-129.02, and rules promulgated pursuant to that section;

(3) Members of the Army, Navy, Air Force, or Marine Corps of the United States or of the National Guard or Organized Reserves when on duty, or to the regularly enrolled members of any organization duly authorized to purchase or receive such weapons from the United States;  provided, that such members are at or are going to or from their places of assembly or target practice;

(4) Officers or employees of the United States duly authorized to carry a concealed pistol;

(5) Any person engaged in the business of manufacturing, repairing, or dealing in firearms, or the agent or representative of any such person having in his or her possession, using, or carrying a pistol in the usual or ordinary course of such business;  and

(6) Any person while carrying a pistol, transported in accordance with § 22-4504.02, from the place of purchase to his or her home or place of business or to a place of repair or back to his or her home or place of business or in moving goods from one place of abode or business to another, or to or from any lawful recreational firearm-related activity.