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Firearms Examination Section

Metropolitan Police Department Headquarters
Henry J. Daly Building
300 Indiana Avenue, NW
Room 1064
Washington, DC 20001
Phone: (202) 727-4416
Fax: (202) 347-2857

The mission of the Firearms Examination Branch is to provide forensic support to the members of the Metropolitan Police Department and other law enforcement agencies by performing chemical, functional, and microscopic analysis on tools, tool marks, firearms, and firearm-related evidence.

Hours of Operation

The Firearms Examination Branch is open from 6:30 am – 5 pm, Monday – Friday, excluding legal public holidays.

Services and Operations

Some of the key services provided by the Firearms Examination Branch include the following:

  • Test fires
  • Computer imaging
  • Serial number restoration
  • Crime case analysis
    • Firearm to bullet
    • Firearm to cartridge case
    • Bullet-to-bullet
    • Cartridge case-to-cartridge case
  • Trajectory analysis (in-house or on-site)
  • Pre-trial consultation
  • Expert course testimonies
  • Forensic research
  • Maintaining reference collection (firearms, ammunition, and literature)
  • Training

Other services offered:

  • Community Outreach. Members of the Firearms Examination Branch provide live demonstrations and informational seminars to churches, DC public schools and PSA meetings, upon request and based on availability. Lectures are routinely conducted to educate our internal and external customers on the myriad services provided by the branch.
  • Lectures. Lectures are given in conjunction with training courses at the Maurice T. Turner Jr., Institute of Police Science, including Homicide School, Basic Investigators Training, Crime Scene Search School, Force Investigation Training, and Gun Recovery School. External training includes semi-annual lectures provided to the United States Attorneys Office, the Public Defender Service and the DC Attorney General's Office. Police officials, diplomats and dignitaries from all over the world tour the Firearms Examination Branch when visiting the Metropolitan Police Department.
  • Tours. Tours are given to many high school and college students, as well as to personnel from other forensic laboratories and the media.


Firearms Examiners use a comparison microscope to determine whether or not a fired bullet, cartridge case or shotshell case was fired from or in a particular firearm, to the exclusion of all other firearms. The comparison is based on the individual marking left on fired ammunition components that is unique to a particular firearm.


Microscopic examination and chemical processing performed on ammunition components can determine whether or not:

  • Ammunition component was fired in/from the firearm/barrel
  • Ammunition component was not fired in/from the firearm/barrel
  • Cannot determine whether or not the ammunition component was fired in/from the firearm barrel.

Gunshot Residue and Operations

  • Microscopic examination and chemical processing performed on clothing can determine:
  • Presence or absence of gunshot residues
  • Whether its appearance is consistent with the passage of a bullet
  • Muzzle-to-garment distance
  • Testing for shot pattern

Requesting Information and Examinations

Authorized personnel (law enforcement, legal personnel, etc.) may request information and examinations from the Firearms Examination Branch. Officers responding for test fire must have the PD163/PD379 if an arrest was made along with the PD81 with barcode information. Evidence coming in via crime scene/mobile crime with a PD698A, PD668, and PD81 with barcode information is retained for examination or sent back with contributor. All MPD paperwork must have the PSA. Outside agencies must have their arrest paperwork, along with any other applicable documents in reference to the case.

Priority requests can be completed for a MPD detective who is involved in the case or by the AUSA. A letter from the AUSA can be sent requesting a specific examination be performed.

Freedom of Information Act (FOIA) and Discovery request should go through the FOIA Office and then be directed to the branch official.