ATF - Also BATF or BATFE. Bureau of Alcohol, Tobacco, Firearms, & Explosives
BATFE - Also ATF or BATF. Bureau of Alcohol, Tobacco, Firearms, & Explosives (often shortened to BATF or ATF)
BJS - Bureau of Justice Statistics
BLM - Bureau of Land Management
BOP - Federal Bureau of Prisons
CDC - Centers for Disease Control
CIA - Central Intelligence Agency
CITES - Convention on International Trade in Endangered Species of Wild Fauna and Flora
CMP - Civilian Marksmanship Program (formerly DCM)
COTUS - Constitution of the United States, less often Congress of the United States
DA - Department of the Army
DARPA - Defense Advanced Research Projects Agency
DCM - Dept of Civilian Marksmanship (now defunct as an organization; see CMP)
DEA - Drug Enforcement Administration
DHS - Department of Homeland Security
DIA - Defense Intelligence Agency
DLA - Defense Logistics Agency
DMA - Defense Mapping Agency
DOC - Department of Commerce
DOD - Department of Defense
DOE - Department of Energy
DOI - Department of the Interior
DOJ - Department of Justice
DOL - Department of Labor
DOS - Department of State
DOT - Department of Transportation
EAR - Export Administration Regulations
EO - Executive Order
FAR - Federal Acquisition Regulation
FBI - Federal Bureau of Investigation
FEMA - Federal Emergency Management Agency
FISA - Foreign Intelligence Surveillance Act. A law which provides limitations on U.S. intelligence surveillance activities. Also sometimes used to refer to the court (FISC) which was created by the FISA to oversee requests for surveillance taking place inside the U.S.
FOPA - Firearms Owner Protection Act of 1986. The FOPA relaxed many onerous restrictions imposed by the GCA but included a "poison pill" called the Hughes amendment which closed the registry for machineguns, effectively limiting the number of transferrable machineguns in the U.S. from that point forward.
FS - Forest Service
FTC - Federal Trade Commission
FWS - Fish and Wildlife Service
GAO - General Accounting Office
GCA - Gun Control Act of 1968. The GCA of 1968 implemented the federal licensing requirements for firearms dealers as well as restrictions on shipping/mailing firearms and on interstate transfers of firearms.
HUD - Housing and Urban Development
IAEA - International Atomic Energy Agency
ICAO - International Civil Aviation Organization
INS - Immigration and Naturalization Service
INTERPOL - International Criminal Police Organization
IRS - Internal Revenue Service
ITAR - International Traffic in Arms Regulations. ITAR restrictions are often counterintuitive, making the international shipment of firearms, firearms parts and even firearms accessories such as scopes a legally risky proposition.
ITC - United States International Trade Commission
JAG - Judge Advocate General
JBT - jack booted thug. Commonly used as a pejorative term referring to federal law enforcement agencies.
JCS - Joint Chiefs of Staff
NATO - North Atlantic Treaty Organization
NCIS - Naval Criminal Investigative Service
NFA - National Firearms Act (1934). The NFA, among other things implemented the federal requirement for registration of machineguns, silencers, and short barrel long guns.
NHTSA - National Highway Traffic Safety Administration
NIJ - National Institute of Justice
NPS - National Park Service
NSA - National Security Agency
OSS - Office of Strategic Services (predecessor to the CIA)