For other acronyms, try Acronymfinder

Misc. Useful Acronyms

2A 2nd Amendment
ACE Alert, Cover, Evacuate [exec protection]
ACOG Advanced Combat Optical Gunsight
ACP Automatic Colt Pistol
AE Action Express
AF Alternative Force
AFAIK As Far As I Know
AIC Agent in Charge
AOP Assault on Principal [exec protection]
AOW Any Other Weapon (zip guns, other non-standard small-bore firearms)
AWB Assault Weapons Ban (part of the 1994 Crime Bill) [legislation]
BAR Browning Automatic Rifle
BC Ballistic Coeffecient
BF BoyFriend
BFF Best Friends Forever
BFO Blinding Flash of the Obvious
BG Bad Guy, or Big Grin
BHP Browning Hi-Power
BMG Browning Machine Gun
BOB Bug-Out Bag (or "Go Bag")
BOHICA Bend Over, Here It Comes Again
BP Black Powder
BPCR Black Powder Cartridge Rifle
BTT Back To Top
BTW By The Way
BUG Back-Up Gun (second or third gun carried in case the primary malfunctions)
CCW Concealed Carry Weapon (may refer to the license, or to the activity itself)
CHL Concealed Handgun License
CIAO This is not an acronym. It's Italian for "bye."
COD Cash On Delivery
COM Center Of Mass
CONUS CONtinental United States
CQB Close-Quarters Battle
CQC Close-Quarters Combat
CRISAT Cooperative Research Into Small Arms Technology
CRPA Certified Royal Pain in the A--
CUP Copper Units of Pressure; a method of measuring chamber pressure, most common with shotguns
DA Double Action
DAO Double Action Only
DARFC Duck And Run For Cover
DD Destructive Device (generally bombs and large-bore weapons)
DFTT Don't Feed The Troll
DOA Dead On Arrival [police]
DPS Department of Public Safety (most states have them)
DVC Diligentia Vis Celeritas (latin for Accuracy, Power, Speed)
EDC Every Day Carry
EDP Emotionally Disturbed Person [NYPD]
EIN Employer Identification Number
EO Executive Order
FFL Federal Firearms License or Licensee
FPS Feet Per Second
FTE Failure to Extract
FTF Face To Face (referring to non-FFL-mediated gun transfers)
FTF Failure to Feed
FTLOG For The Love Of God
FUBAR F---ed Up Beyond All Recognition
FWIW For What It's Worth
FYI For Your Information
GC gas check; a copper-zinc alloy cup used as gilding to protect the base of lead bullets from hot gas obduration during internal ballistics.
GD&R Grin, Duck, & Run
GF GirlFriend
GG Good Guy
GI Government Issue
GMT Greenwich Mean Time (timezone, equivalent to Zulu/UTC)
HAND Have A Nice Day
HD Home Defense
HDC Home Defense Carbine
HMG Heavy Machine Gun
HSP Highly Sensitive Person
HTH Hope That Helps
IANAL I Am Not A Lawyer
IDLE International Date Line East
IDLW International Date Line West
IINM If I'm Not Mistaken
IIRC If I Remember Correctly
IMHO In My Humble Opinion
IMNSHO In My Not So Humble Opinion
IMO In My Opinion
IRL In Real Life
IWB Inside WaistBand
JBT Jack Booted Thug
JMB John Moses Browning
JMO Just My Opinion
KISS Keep It Simple, Stupid
KYPD Keep Your Powder Dry
LDA Light Double Action
LE Law Enforcement
LEA Law Enforcement Agency
LEO Law Enforcement Officer/Official
LLEA Local Law Enforcement Agency
LMAO Laughing My A-- Off
LMG Light Machine Gun
LNIB Like New In Box, usually means the item looks new but has been lightly used (see also NIB)
LOL Laughing Out Loud
LOS Line Of Sight
MG Machine Gun
MIM Metal Injection Molding
MOA Minutes Of Angle (angular measurement, 1/60 of a °, 360° in a circle)
MOB Middle Of Back
MOS Military Occupational Specialty
MV Muzzle Velocity
NAP Non-Aggression Principle (and criticism)
NIB New In Box, usually means the item has not been used since bought, but can also mean LNIB.
NOYB None Of Your Business
OAL OverAll Length
OMG Oh My God
OODA (loop) Observe, Orient, Decide, Act (coined by USAF Col John Boyd)
OOTB Out Of The Box
ORM-D Other Regulated Materials - Domestic (seen on boxes of shipped ammo)
OT Off-Topic
OTOH On The Other Hand
OWB Outside the WaistBand
PASGT Personnel Armor System for Ground Troops
PBR Point Blank Range
PDW Personal Defense Weapon
PHB Pointy-Haired Boss (Dilbert reference, a boss without a clue)
PITA Pain In The A--
POA Point Of Aim
POI Point Of Impact
POI Person Of Interest
POS Piece Of S---
PSI Pounds per Square Inch
PT Physical Training
PTL&PTA Praise The Lord & Pass The Ammunition
REMF Rear Eschelon Mother F---er (derogatory name for a non-combatant in a combat zone or a military occupational specialty that would keep one from seeing combat)
RINO Republican In Name Only (a liberal in conservative clothing)
RKBA Right to Keep and Bear Arms
ROTFL Rolling On The Floor Laughing
ROTFLMAO Rolling On The Floor Laughing My A-- Off
SA Single Action
SAA Single Action Army (famous Colt revolver design that shows up in Westerns)
SAK Swiss Army Knife
SD Self Defense; Sectional Density (weight [lbs] to cross-section area [in^2])
SHTF S--- Hits The Fan
SKS Samozaryadnaya Karabina Simonova, or Self-loading carbine Simonov. Sergei Gavrilovich Simonov was one of the old Soviet Union's foremost arms designers. The rifle was adopted by the USSR in 1945, and was made both there and in China.
SLR Self-Loading Rifle
SMG Sub-Machine Gun
SNAFU Situation Normal: All F---ed Up
SO Significant Other (boyfriend/girlfriend/husband/wife)
SOB Small Of Back (6 o'clock carry)
SOP Standard Operating Procedure
SOT Special Occupational Tax license (administered by the BATFE)
SWAT Special Weapons And Tactics
SxS Side by Side (i.e. a shotgun)
TEOTWAWKI The End Of The World As We Know It
TIA Thanks In Advance
TID Tax ID number
TLA Three Letter Acronym
TPTB The Powers That Be
TTW Taunting The Wookie (someone known to rip arms out of sockets when inflamed)
TU Tits Up (military origin, meaning f---ed; often spelled phonetically as "Tango Uniform")
URL Uniform Resource Locator
UTC Universal Time Coordinate (timezone, equivalent to Zulu/GMT)
VCA Violent Criminal Assailant
WTF What The F---?
WTSHTF When The S--- Hits The Fan
WYSIWYG What You See Is What You Get
YMMV Your Mileage May Vary

Bullet Design

AP Armor Piercing
API Armor Piercing, Incendiary
APT Armor Piercing, Tracer
BBWC Bevel Base WadCutter
BT BoatTail
FMJ Full Metal Jacket
FP Flat Point
HP Hollow Point
J Jacketed
JFP Jacketed Flat Point
JHC Jacketed Hollow Cavity
JHP Jacketed Hollow Point
L Lead
LRN Lead Round Nose
LSWC Lead Semi-WadCutter
LWC Lead WadCutter
RN Round Nose
SJ Semi-Jacketed
SJHP Semi-Jacketed Hollow Point
SP Soft Point
SWC Semi-WadCutter
TC Truncated Cone
TMJ Total Metal Jacket
WC WadCutter

National Membership-type RKBA Organizations

AKTI American Knife and Tool Institute
CCRKBA Citizens' Committee for the Right to Keep and Bear Arms
GOA Gun Owners of America
JPFO Jews for the Preservation of Firearms Ownership
Kniferights Knife Rights
NRA National Rifle Association
SAF Second Amendment Foundation
SAS (2AS) Second Amendment Sisters

Other Organizations (both pro and anti-gun)

ACLU American Civil Liberties Union
ARFCOM AR15.com
ASA Australian Shooting Association
BCPGV Brady Center to Prevent Gun Violence
BF Blade Forums
CAS Cowboy Action Shooting
CLDF Civil Liberties Defense Foundation
COA Citizens of America
CPHV Center to Prevent Handgun Violence (Brady Center offshoot)
DU Democratic Underground
FOP Fraternal Order of Police
FOUP Firearm Owners Unification Project
GT GlockTalk
HCI Handgun Control Inc. (Brady Center)
IALEFI International Association of Law Enforcement Firearms Instructors
IDPA International Defensive Pistol Association
IPSC International Practical Shooting Confederation
KABA Keep And Bear Arms
LEAA Law Enforcement Alliance of America
MMM Million Mom March
NRAILA National Rifle Association Institute for Legislative Action
NSSF National Shooting Sports Foundation
SAAMI Sporting Arms and Ammunition Manufacturers Institute
SASS Single Action Shooting Society
SATF Second Amendment Task Force
SDF Self Defense Forums
SHOTShow Shooting, Hunting, and Outdoor Travel Show
TFL The Firing Line
THR The High Road
TRT Tyranny Response Team
USPSA United States Practical Shooting Association

Government/Military/International

AG Attorney General
ANL Argonne National Laboratory
ATF bureau of Alcohol, Tobacco, and Firearms (see BATFE)
BATF Bureau of Alcohol, Tobacco, and Firearms (see BATFE)
BATFE Bureau of Alcohol, Tobacco, Firearms, and Explosives (new name)
BIA Bureau of Indian Affairs
BLM Bureau of Land Management
BNL Brookhaven National Laboratory
BXA Bureau of Export Administration
CBP u.s. dhs bureau of Customs and Border Protection
CDC Center for Disease Control
CENTCOM Central Command
CERT Computer Emergency Response Team (part of SEI)
CIA Central Intelligence Agency
CIC CounterIntelligence Center
CIFA CounterIntelligence Field Activity (military)
CIO Central Imagery Office (see NIMA)
CMP Civilian Marksmanship Program (formerly DCM)
CNC dci Crime and Narcotics Center
CSE dci Center for Security Evaluation
CTC dci CounterTerrorist Center
DARO Defense Airborne Reconnaissance Office
DARPA Defense Advanced Research Projects Administration
DASD Deputy Assistant Secretary of Defense
DCID Director of the Central Intelligence Directive
DCM Department of Civilian Marksmanship (now defunct, see CMP)
DEA Drug Enforcement Agency
DHS Department of Homeland Security
DIA Defense Intelligence Agency
DISA Defense Information Systems Agency
DISN Defense Information Systems Network
DLA Defense Logistics Agency
DOC Department of Commerce
DOD Department of Defense
DOE Department of Energy
DOE Department of Education (DOEdu)
DOI Department of the Interior
DOJ Department of Justice
DOL Department of Labor
DOT Department of Transportation
DPS Defense Protective Service - see PFPA
DSS Defense Security Service
DSS Diplomatic Security Service
DTIC Defense Technical Information Center
EPA Environmental Protection Agency

FAA Federal Aviation Administration
FBI Federal Bureau of Investigation
FCC Federal Communications Commission
FDA Food and Drug Administration
FEC Federal Elections Commission
FEMA Federal Emergency Management Agency
FFA Federal Firearms Act of 1938 - set up the FFL licensing scheme [legislation]
FinCEN Financial Crimes Enforcement Network
FISA Foreign Intelligence Surveillance Act

FNAL Fermi National Accelerator Laboratory
FOPA Firearm Owners Protection Act of 1986 - banned AP ammo and closed the MG registry [legislation]
GAO General Accounting Office
GCA Gun Control Act of 1968 - restricted firearms purchasing and transfer [legislation]
GPO Government Printing Office
GSA General Services Administration
HHS department of Health and Human Services
HPSCI House Permanent Select Committee on Intelligence
HUD department of Housing and Urban Development
IC Intelligence Community
IC/EXCOM Intelligence Community/EXecutive COMmittee
ICC Interstate Commerce Commission
ICC Interstate Commerce Clause (Article 1, Section 8)
ICE Immigration and Customs Enforcement
IDA Institute for Defense Analyses
INEEL Idaho National Engineering and Environmental Laboratory
INR department of state's bureau of Intelligence aNd Research
INS Immigration and Naturalization Service, now the BCIS
Interpol Interpol (see OIPC, ICPO)
IOB president's Intelligence Oversight Board
IRS Internal Revenue Service
JAG Judge Advocate General
JCCC Joint Communications Control Center
JPL Jet Propulsion Laboratory
LANL Los Alamos National Laboratory
LBNL Lawrence Berkeley National Laboratory
LL Lincoln Laboratory
LLNL Lawrence Livermore National Laboratory
NAIC National Astronomy and Ionosphere Center
NARA National Archives and Records Administration
NASA National Aeronautics and Space Administration
NATO North Atlantic Treaty Organization
NCBI National Center for Biotechnology Information
NCGR National Center for Genome Resources
NCI National Cancer Institute
NCI-FCRDC NCI - Frederick Cancer Research and Development Center
NCIX National CounterIntelligence eXecutive
NDIC National Drug Intelligence Center
NFA National Firearms Act of 1934 - taxed certain firearms and firearm components [legislation]
NFIB National Foreign Intelligence Board
NIC National Intelligence Council
NIH National Institute for Health
NIMA National Imagery and Mapping Agency
NIPC National Infrastructure Protection Agency
NLM National Library of Medicine
NOAA National Oceanic and Atmospheric Administration
NPC dci NonProliferation Center
NREL National Renewable Energy Laboratory
NRO National Reconnaissance Office
NSA National Security Agency
NSC National Security Council
NTIC National Threat Integration Center
OASD Office of the Assistant Secretary of Defense (C3I)
ODCI Office of the Director of Central Intelligence (CIA)
OFAC Office of Foreign Asset Control
OIG Office of the Inspector General
OIP department of justice's Office of Information and Privacy (FOIA)
OIPR Office of Intelligence Policy and Review (under DOJ)
OMB Office of Management and Budget
OPM Office of Personnel Management
ORNL Oak Ridge National Laboratory
OSD Office of the Secretary of Defense
OSHA Occupational Safety Hazards Association
OSS Office of Strategic Services (predecessor of the CIA)
PFIAB President's Foreign Intelligence Advisory Board
PFPA Pentagon Force Protection Agency
PNL Pacific Northwest National Laboratory
POTUS President Of The United States
PPPL Princeton Plasma Physics Laboratory
SBA Small Business Administration
SCOTUS Supreme Court Of The United States
SEC Securities and Exchange Commission
SEI Software Engineering Institute
SIPRNET Secret Internet Protocol Router Network
SLAC Stanford Linear Accelerator Center
SNL Sandia National Laboratory
SRS Savannah River Site
SSA Social Security Administration
SSCI Senate Select Committe on Intelligence
STRATCOM Strategic Command
TIGR The Institute for Genetic Research
TJNAF Thomas Jefferson National Accelerator Facility
TSA Transportation Security Administration
TTIC Terrorist Threat Integration Center (housed in the CIA)
UI/MRL U. Ill. Frederick Seitz Materials Research Laboratory
UN United Nations
UNSC United Nations Security Council
USAF U.S. Air Force
USCG U.S. Coast Guard
USCIS U.S. Citizenship and Immigration Services (INS)
USD UnderSecretary of Defense for policy
USDA U.S. Department of Agriculture
USGS U.S. Geological Survey
USMC U.S. Marine Corps
USN U.S. Navy
USNBC U.S. National Central Bureau
USNO U.S. Naval Observatory
USPTO U.S. Patent and Trademark Office
USSC U.S. Strategic Command
USSC U.S. Sentencing Commission (often meant to refer to the SCOTUS)
USSS U.S. Secret Service
VA Dept. of Veterans Affairs
WPA War Powers Act

Terminology

Anneal To soften metal by heating. Used to extend the useful reloading life of brass cartridge case necks by softening them and permitting more reloading operations to be performed before the work hardening effect of the cold, forced reshaping of the resizing operation causes metal fatigue in the neck area and makes the brass case unusable for further reloading. Brass and copper are annealed by fast cooling, usually by quenching, from a heated condition. Steel is annealed by a slow cooling. Quenching of steel from high heat has the opposite effect from the same treatment of brass and copper.
Anti an individual who opposes the RKBA for private citizens
Bearing Surface That portion of a bullet that contacts the bore of the barrel as it travels from chamber to muzzle. Sufficient bearing surface is required for good accuracy.
Bedding material and/or methods used to fit rifle action to a stock.
Bore the inside of a firearm's barrel.
Bore sight to align the sights of a firearm by sighting through the barrel bore
Brisance the "shattering" effect of explosives; the burn rate, in terms of acceleration, i.e., how quickly is the maximum burn rate of an explosive mass reached?
Bullet the projectile which is expelled from a firearm's barrel at firing
Burn rate the relative speed at which gun powders burn (explode) This is determined by the size and shape of granules, amount and nature of any coatings and, in some cases, specific physical design of the granules, such as perforations, tubes, rods, ball (beads) or disk shapes (flattened beads).
Cal. Caliber (inches or millimeters); projectile (bullet) diameter or diameter of some specifically defined point in the bore of a barrel; the nominal or approximate diameter of a bore expressed similarly. NOT the same as a cartridge chambering! Caliber is diameter only. .223 Remington is not a caliber. It is a chambering. The number .223 alone, however is understood to mean the .223 Remington, but literally is a caliber. There are several chamberings that use the .223 caliber of bullet or bore. .30-'06 is a chambering. It uses a .308 caliber bullet.
Cartridge completed assembly, comprised of a case (the central component), primer (for ignition), powder (primary energy source) and bullet (projectile). The cartridge is placed into the chamber and confined by a breech device for firing.
Chamber the portion of a firearm which contains the cartridge at firing.
Chambering i.e., "This rifle is available in the following chamberings: "; Specific machined dimensions to the interior rearmost portion of a barrel which results in a chamber that will accept and safely fire one cartridge design only, i.e., .30-'06 Springfield, .270 Winchester, .223 Remington, .38-55 Winchester-Ballard, .45-'70 Government, etc. Although acceptable chamber dimensions are defined and accepted throughout the firearms industry by the ANSI-approved SAAMI, there are many "wildcat" and "improved" variations of standard SAAMI chamberings in use.
Charge quantity of powder; usually in grains. One avoirdupois pound equals 7,000 grains.
Choke in a shotgun, the taper in the last few inches of the barrel. This is usually a tightening of the bore to a slightly smaller diameter from the actual gauge measurement of the barrel. Some typical choke names, from least to most taper, are: cylinder (no taper), improved cylinder (or simply: "improved"), modified cylinder ("modified") and full choke ("full"). This is not a complete list, but typical.
Class III Refers to the Class III FFL required to deal in NFA items (full-auto, suppressors, etc.)
Clip A strip of metal that is used to hold cartridges together to facilitate the loading into (usually) an internal rifle magazine.
Condition 1 Pistol: Full magazine, cartridge in chamber, hammer cocked, safety on. AKA "cocked and locked."
Condition 2 Pistol: Full magazine, cartridge in chamber, hammer down, safety off.
Condition 3 Pistol: Full magazine, chamber empty.
Condition 4 Pistol: Full magazine separate from gun, chamber empty.
Condition Red Under attack.
Condition Orange Heightened awareness; alert to potential threats.
Condition Yellow Normal awareness of the environment.
Condition White Unawareness of the environment.
Components (reloading) individual components that make up the "recipe" for a hand loaded cartridge. The four components are: primer, case, bullet and powder.
Cruiser Ready Shotgun: Full magazine, chamber empty, hammer down, safety off.
Cylinder Gap the distance between the front of the cylinder and the rear of the barrel in a revolver.
GA gauge (also: ga.)
Headspace measurement between two points in a chamber which are the confining boundaries of cartridge movement during chambering and firing. Insufficient headspace hinders complete chambering of the cartridge. Excessive headspace permits case stretching and can permit case separation, which will permit high pressure gas leakage during the firing/pressure cycle. Very dangerous to equipment and shooter. Headspace is defined and measured differently for each case design. Rimless, rimmed and belted bottleneck cases each have a method unique to the design and a measurement specific to the chambering. Straight walled cases, rimless and rimmed, also have unique methods and cartridge-specific measurements.
Mag. magazine; magnum; also: mag.
Magazine ammunition holders that are equipped with a spring to move the ammo, these are not clips.
mm MilliMeters
Ogive a measure of the curvature forward portion of the bullet. The radius of the ogive is usually expressed in multiples or fractions of the caliber.
Throat leade, freebore. That portion of the barrel bore immediately forward of the chamber. In some rifle chamber designs, the throat may be long and may transition into a relatively slow taper to full depth of lands and grooves (rifling). In other rifle designs the throat is relatively short and the transition to full depth rifling is abrupt, although all barrels have some taper from throat to full depth rifling. The immediate effect of the two extremes in design is to determine the maximum distance a bullet may protrude out the front of the case. This determines the final overall length of the loaded cartridge, for a given bullet shape.
Tin Foil Hat These provide excellent protection against mind control rays which may or may not be transmitted by aliens, the CIA, or the military.
Weapons Free Military weapons control policy that allows engagement of anything not positively identified as friendly
Weapons Tight Military weapons control policy that allows engagement of anything positively identified as hostile
Weapons Hold Military weapons control policy that allows engagement only in self defense.

License/Permit Abbreviations (*'d entries are commonly used in place of the less common ones)

*CCW Concealed Carry (of) Weapon(s) (MO)
CDWL Concealed Deadly Weapons License (KY)
CFP Concealed Firearm Permit (UT, NV)
*CHL Concealed Handgun License (AR, NM, OR, TX)
CHP Concealed Handgun Permit (AK, LA, NC)
CPL Concealed Pistol License (MI, WA)
CWL Concealed Weapon License (FL, ID, OK)
CWP Concealed Weapon Permit (AZ, CO, MT, ND)
FL Firearms License (GA)
FP Firearms Permit (MS)
*LTC License To Carry (CA, IN, MA, NY)
LTCCH License To Carry a Concealed Handgun (OH)
LTCF License To Carry Firearms (PA)
PL Pistol License (AL, NH)
PTC Permit To Carry (CT, IA, ME, MD, MN, NJ)
misc (HI, IL, NE, RI...)