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AR15 related Acronyms


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Here is a brief list of acronyms that may help those that are new to the AR platform and related items.


A1 - Of or referring to a characteristic of the M16A1 (for example, an A1 rear sight)
A2 - Of or referring to a characteristic of the M16A2 (for example, an A2 flash hider)
A3 - Of or referring to a characteristic of the M16A3, or (in civilian parlance) a flat-top receiver. Note that the M16A3 is essentially just a full-auto M16A2, but civilian manufacturers began using the term A3 for flat-top receivers before the military adopted the M16A3 and M16A4, so there is divergence between military and civilian usage of the term "A3". Without a definitive military context, it is most likely that "A3" refers to a flat-top, civilian upper receiver. Note also that some civilian manufacturers call their flat-tops A3, others A4.
A4 - Of or referring to a characteristic of the M16A4 (for example, a flat-top A4 upper receiver)
ABC - Armalite, Bushmaster and Colt (use to be considered by many to be the top three manufacturers of AR-15s. This is no longer the case)
ACOG - Advanced Combat Optical Gunsight
ACR - Advanced Combat Rifle (a late 1980's weapon development program intended to replace the M16)
AD - Accidental Discharge (a non-negligent unintentional discharge of a weapon that could not have been reasonably forseen and prevented - e.g. a caused by an unexpected mechanical failure)
AOW - Any Other Weapon (any weapon capable of discharging a shot that is not otherwise categorized under the NFA)
AR - ArmaLite
ARD - Anti-Reflection Device (a device placed on the objective of an optic to reduce reflections and glare. Typically attached to Aimpoint Comp M2, M3, and M4)
AWB - Assault Weapons Ban (from 1994-2004; some states have enacted their own AWB)

BAC - Bindon Aiming Concept (the idea behind Trijicon optics like the ACOG that are designed to combine the rapid acquisition of unmagnified sights with the accuracy of traditional magnified scopes. Requires the use of both eyes in the manner of OEGs.)
BBL - Barrel
BC - Ballistic Coefficient (a measure of a bullet's ability to slip through the air unhindered by drag - higher values indicate more streamlined bullets)
B/C/CH - Bolt, Carrier, Charging Handle (the assembly of parts that cycles rounds into the chamber)
BCG - Bolt Carrier Group (the bolt, bolt carrier, gas key, cam pin, etc.)
BDC - Bullet Drop Compensator (a mechanism in a sight to compensate for a bullet's trajectory drop at long distances)
BFA - Blank Firing Adapter
BG - Battlegrip (enhanced handgrip made by TangoDown )
BH - Black Hills (manufacturer of a variety of new, remanufactured and special purpose ammunition)
BHO - Bolt Hold Open (a mechanism that holds the bolt open when the magazine is empty, allowing for faster reloads)
BIY - Build It Yourself
BL - Bayonet Lug
BM - Bushmaster (manufacturer of many AR-style rifles; now owned by the Freedom Group along with DPMS and Remington)
BOB - Bug Out Bag (a bag filled with the necessities you will need to survive in the event you are forced to flee your home on a moment's notice)
BOHICA - Bend Over Here It Comes Again
BRASS - Breathe-Relax-Aim-Slack-Squeeze (mnemonic for steps of accurate shooting - there are many variants of this including Breath-Relax-Aim-Sight-Squeeze and Breath-Relax-Aim-Squeeze)
BRASSF - Breathe-Relax-Aim-Stop-Squeeze-Follow Through (mnemonic for steps of accurate shooting as taught by the USMC)
BRD - Black Rifle Disease (a mysterious ailment in which the sufferer develops an insatiable desire for more and more AR-15s)
BSZ - Battle Sight Zero
BT - Boat Tail (a bullet that tapers at the back like the tail of a boat rather than cuts off at a right angle)
BUIS - Backup Iron Sight
BZO - Battle Sight Zero

C3 - Class 3 (a class of restricted weapons as defined by the NFA, including machineguns, supressors, short-barrelled rifles, short-barrelled shotguns, etc.)
CAR - Carbine
CCH - Cut Carry Handle (a carry handle cut down to form a BUIS)
CCO - Close Combat Optic (an optic designed for close range use, typically low power, parallax free and with long eye relief. The Aimpoint M68 is an example.)
CH - Charging Handle
CLE - Compass Lake Engineering (manufacturer of competition service rifles and space guns )
CLIN - Contract Line Item Number
CLP - Cleaner, Lubricant, Protectant (all-purpose gun maintenance product)
CMP - Civilian Marksmanship Program
CMMG - Not an acronym, just a name (retailer of AR-15s, parts and accessories)
CMT - Continental Machine and Tool (contract manufacturer of AR15 uppers and lowers)
CQB - Close Quarters Battle
CQ/T (also CQT) - Close Quarters / Tactical (a 1-3x optic made by Leupold and designed for close quarters battle with some mid-range capability as well)
C&R - Curios and Relics (firearms that are officially recognized as collectible due to some unique quality such as age. The ATF maintains a list of qualified C&R firearms that C&R license holders can purchase via interstate commerce without the services of an FFL dealer.)
CTR - Compact/Type Restricted (an adjustable carbine stock made by Magpul, with a friction lock feature)

DC - Dust Cover
DCH - Detachable Carry Handle
DCM - Director of Civilian Marksmanship (replaced by the CMP)
DD - Daniel Defense (manufacturer of free floating railed handguards, slings and accessories)
DD - Destructive Device (an explosive, incendiary, or poison gas device as defined by the NFA)
DEWAT - De-activated War Trophy (a machine gun whose barrel has been plugged and welded to the receiver and whose chamber has been welded shut, rendering it unserviceable but still subject to the regulations of the NFA)
DI - Direct Impingement (firearm operating system where the action is cycled directly by the cartridge gasses. Most famously used in the AR15 and M16 series of rifles.)
DIAS - Drop-In Auto Sear (a device used to convert a semi-automatic gun to full-auto. By itself considered to be a machine gun under the NFA, and unregistered ones are illegal to even possess with, let alone install in, the guns they convert)
DOD - Department Of Defense
DPMS - Defense Procurement Manufacturing Services (builder of AR-15 rifles and supplier of parts and accessories)
DRMO - Defense Reutilization Marketing Office (an office of the DRMS)
DRMS - Defense Reutilization Marketing Service (a government agency that disposes of excess property received from the military services)
DSA - D.S. Arms (specializes in FAL rifles, but also sells AR-15 parts and accessories)

EA - Essential Arms (manufacturer of AR-15 lowers, stocks and parts)
EBR - Evil Black Rifle (a twist on the gun-grabbers' propaganda, embraced by supporters of the RKBA to both endearingly and sarcastically refer to military-style rifles such as the AR-15)

FA - Forward Assist
FA - Full Auto
FAR - Featherweight Assault Rifle
FCG - Fire Control Group (the hammer, trigger, disconect, springs and selector)
FDE - Flat Dark Earth (a tan-brown color making inroads as a replacement for black in weapon coloring)
FF - Free Float/Floated/Floating
FFL - Federal Firearms License/Licensee (a license that permits one to sell & transfer guns in interstate commerce, or the holder of that license)
FH - Flash Hider
FMJ - Full Metal Jacket (a bullet that is fully encased in a metal jacket)
FMJBT - Full Metal Jacket Boat Tail (a FMJ BT bullet)
FN - Fabrique Nationale (famous Belgian small arms manufacturer)
FNMI - FN Manufacturing, Inc. (Division of Fabrique Nationale located in South Carolina that makes M16s, M240s and M249s for the military)
FP - Firing Pin
FS - Flash Suppressor
FSB - Front Sight Base
FSP - Front Sight Post
FST - Front Sight Tower
FTE - Fail To Eject/Extract (please substitute the more precise FTEj or FTEx as appropriate to make clear your intention)
FTF - Fail To Feed (if used without an unambiguous context, this acronym may be confused with "Fail To Fire" as listed below)
FTF - Fail To Fire (if used without an unambiguous context, this acronym may be confused with "Fail To Feed" as listed above)
FUBAR - Fouled Up Beyond All Recognition (substitute more colorful adjective for "Fouled" as desired)

GCA - Gun Control Act of 1968 (The law that, among other things, established the FFL license system, set a minimum age to purchase guns, and banned the import of "non-sporting" guns, eventually including military-stiyle guns)

HBAR Heavy Barrel
HG - Handguard
HP - Hollow Point (a bullet with a hollow cavity at the tip)
HSLD - High Speed, Low Drag (of or relating to special forces and other highly skilled operators)

IAD - Immediate Action Drill (a sequence of actions performed in response to a situation requiring immediate and instinctive resolution - in this context a weapon malfunction)
IBZ - Improved Battlesight Zero (All purpose zero invented by Lt. Colonel Chuck Santose. Set at 50 yards, it gives a very flat trajectory out to 250 meters.)
ID - Inside Diameter
ID - Involuntary Discharge (an unintentional discharge of a weapon resulting from a physical reaction beyond the shooter's instant control - e.g. a muscle spasm)

JHP - Jacketed Hollow Point (a bullet that is jacketed in metal, but with a hollow cavity at the tip)
JSP - Jacketed Soft Point (a bullet that is jacketed in metal, but with exposed lead at the tip)

KAC - Knights Armament Company (manufacturer of rail adapter systems, sights and accessories - website)
KB - KaBoom (explosive failure of a firearm - caused by problems such as out-of-battery firing, bore obstructions, etc.)
KISS - Keep It Simple, Stupid (an admonition to avoid complexity with its attendant expense and unreliability, also used as an adjective to describe something that adheres to the KISS philosophy)
KMC - Knights Manufacturing Company (manufacturer of rail adapter systems, sights and accessories)
KNS - KNS Precision (manufacturer of small parts such as sight apertures and trigger pins for a variety of rifles)

LC - Lake City (a federally owned, contractor operated plant in Missouri where small arms ammunition is made for the U.S. military)
LCW - Lauer Custom Weaponry (gun refinishing and camouflaging services)
LE - Law Enforcement
LEO - Law Enforcement Officer
LL - Lightning Link (a device for converting a semi-automatic gun to full-auto. By itself considered to be a machine gun under the NFA, and unregistered ones are illegal to even possess with, let alone install in, the guns they convert)
LMT - Lewis Machine and Tool (manufacturer of AR-15 uppers and accessories)
LOP - Length Of Pull (the distance from the face of the trigger to the end of the buttstock)
LPK - Lower Parts Kit
LULA - Loader/Unloader Accessory (for fast loading and unloading of magazines)
LW - Lightweight

M16 - The original full-auto military version of the AR-15 rifle (includes triangular cross-section handguards, early style rear sight that is not adjustable for range, and a 1:12 twist barrel)
M16A1 - Later variant of the M16 that added a forward assist to jam the bolt home when the normal action cycling doesn't)
M16A2 - Later variant of the M16A1 that switched to a range-adjustable rear sight, a 1:7 twist barrel, round cross-section handguards and substituted a three-round burst firing mode for the full-auto mode)
M16A3 - Later variant of the M16A2 that substitutes full-auto firing for the three-round burst mode of the M16A2. Initially adopted by the Navy SEALS)
M16A4 - Later variant of the M16A2 that added a flat-top upper receiver with removable carry handle but maintained the three-round burst firing mode)
M193 - 55 grain FMJBT military cartridge, usable in 1:14 to 1:7 twist barrels
M4 - A 14.5" barrel carbine version of the M16A2. Earlier models have an integral A2 carry handle, later ones have a flat-top upper
M4A1 - A variant of the M4 that includes full-auto fire and a flat-top upper with removable carry handle
M4GERY - A rifle designed to mimic the appearance and function of a true M4, but that isn't an official military M4 (pronounced "em forgery")
M855 - 62 grain FMJBT military cartridge, usable in 1:10 to 1:7 twist barrels
MARPAT - MARine PATtern (a digital camouflage pattern. Examples here, controversy here and here.)
MARS - Multipurpose Aiming Reflex Sight (an Israeli sight that combines a reflex red-dot sight with a laser (visible or IR) aiming light)
MIAD - MIssion ADaptable (a modular grip manufactured by Magpul - website)
MOA - Minute Of Angle (a measure of angular displacement equal to 1/60 of one degree, usually used when discussing group sizes - 1 MOA is roughly 1" at 100 yds)
MOUT - Military Operations on Urbanized Terrain
M&P - Military and Police (A trademark of Swith and Wesson for a line of pistols and AR-15 rifles)
ProofMark.gif - proof mark that indicates Magnetic particle inspection and Proof load firing has been performed on a barrel
MP - Magnetic Particle [inspection/testing] (Magnetic particle inspection is a non-destructive steel inspection method used to ensure that a barrel, for example, is free from metallurgical defects such as cracks. MP is also used as an easily typed representation of the proof mark ProofMark.gif that is sometimes stamped on a part to indicate it has been MP tested.)
MRF - Modular Rail Forend (a rail adapter system made by Troy Industries)
MRP - Monolithic Rail Platform (an integrated AR-15 upper receiver and rail adapter system, made by LMT)
MRS - Modular Rail System (Leitner-Wise's light-weight, quick-change barrel system designed for use with standard AR-15 lowers)
MR/T (also MRT) - Mid Range / Tactical (a line of optics made by Leupold and designed for mid-range capability)
MSTN - Mid-South Tactical Network (retailer of AR-15 related gear and accessories)
MWS - Modular Weapon System

ND - Negligent Discharge (an unintentional discharge of a weapon that reasonably should have been forseen and prevented)
NFA - National Firearms Act (of 1934 - the law governing machine guns, sawed off shotguns, short barreled weapons, suppressors, etc.)
NIB - New In Box (a gun that is still in the original box, unfired after it left the factory)
NICS - National Instant Criminal Background Check System (the system established as part of the Brady Act to check for disqualifying information that would prevent legal transfer of a firearm to a person)
NIW - New In Wrapper (mostly in reference to magazines, which come from the factory wrapped in protective paper or plastic)
NM - National Match (a competition sponsored by the CMP)
NOD - Night Observation Device
NOOB - Newbie (one who is new to a topic and doesn't have much knowledge of it)
NOS - New Old Stock (generally used in connection with an item that can no longer be manufactured new, but that can be sold from existing stock: an item that is chronologically old, but that has been sitting in storage and was never sold at retail or used before)
NRA - National Rifle Association
NSN - National Stock Number (a unique number assigned to each item in the Federal Supply Cataloging System, including parts and accessories for military weapons such as the M16)
NSW - Naval Special Warfare
NTCH - Nose To Charging Handle (a cheek weld [placement of the side of one's face against the stock] where the tip of the nose touches the charging handle, thus giving a consistent position and sight picture)
NVD - Night Vision Device

OAI - Olympic Arms, Inc. (manufacturer of various AR-style rifles)
OAL - Overall Length
OD - Olive Drab (that green color the army is so fond of)
OD - Outside Diameter
OEG - Occluded Eye Gunsight (a sight that projects a dot to the eye but through which you can't actually see the target - hence the term "occluded". It works via binocular vision whereby one eye views the target directly, the other eye views the dot in the sight, and your brain merges the two images together)
OICW - Objective Individual Combat Weapon (possible M16 replacement weapon system that can fire both normal bullets and airburst fragmenting munitions. The XM8 is based on the normal bullet firing component an early OICW entry.)
OTM - Open Tip Match (a type of hollow point bullet designed for long range accuracy)
OPS - Operations (see also OPS-INC just below)
OPS-INC - O. P. Seberger Incorporated (manufacturer of muzzle breaks and silencers for the U.S. military)
OTAL - Offset Tactical Aiming Laser (a laser sight mounted alongside the barrel/handguards/carry handle)

PAFS - Permanently Attached Flash Suppressor (generally permanantly attached in order to bring a barrel's overall length to 16" and thus avoid the legal restrictions on SBRs)
PDW - Personal Defense Weapon (a generally compact weapon designed primarily for defensive rather than offensive operations, for example the FN P90)
PM - Preventative Maintenance
PM - Private Message (see IM)
PMO - Postal Money Order
POA - Point Of Aim
POF - Patriot Ordnance Factory (manufacturer of gas piston AR-15 uppers and rail systems, importer of HK parts from Pakistan Ordnance Factories)
POI - Point Of Impact
PRI - Precision Reflex Incorporated
PRS - Precision Rifle/Sniper (a precision stock made by Magpul, adjustable for height and LOP)
PSD - Personal Security Detail/Detachment (a group of security specialists who travel with and provide personal protection for a high-ranking or valuable person)
PWA - Pac West Arms

Q3131A - M193 ammunition packaged for sale to civilians (may fail to meet some aspect of military standard)
QCB - Quick Change Barrel
QD - Quick Detach

RA - Robinson Armament (manufacturer of the M96 and XCR series of piston operated .223 rifles)
RAS - Rail Adapter System
RDIAS - Registered Drop-In Auto Sear (a DIAS legally registered under the NFA. By itself considered to be a machine gun under the NFA)
RECCE - Reconnaissance (in this context a 16" free floating match barrel upper, ACOG optic, originally used by SEALS)
RIS - Rail Interface System
RLL - Registered Lightning Link (a LL legally registered under the NFA. By itself considered to be a machine gun under the NFA)
ROF - Rate Of Fire
RR - Registered Receiver (a receiver, typically for a machine gun, registered under the NFA)
RRA - Rock River Arms (manufacturer of AR-15 rifles - website)

SAAMI - Sporting Arms and Ammunition Manufacturers' Institute (an association of manufacturers of sporting firearms, ammunition, and components. Often used to distinguish between the sporting .223 chamber [the SAAMI chamber] and the military 5.56 mm chamber )
SAM-R - Squad Advanced Marksman Rifle (20" match barrel upper with Leupold scope, used by the Marines)
SAW - Specialized Armament Warehouse (Colt distributor that caters to military and law enforcement sales)
SAW - Squad Automatic Weapon
SBR - Short-Barreled Rifle (a rifle whose barrel is less than 16" long as defined by the NFA)
SCAR - Special Operations Forces Combat Assault Rifle made by Fabrique National.
SD - Shell Deflector
SDM-R - Squad Designated Marksman Rifle (20" match barrel upper with ACOG scope, used by the Army)
SEAK - Special Edition AK (a custom AK-74 rifle sold as part of a group buy run by AR15.com)
SEBR - Special Edition Black Rifle (a custom AR-15 rifle sold as part of a group buy run by AR15.com)
SF - Special Forces
SF - Surefire (manufacturer of flashlights and weapon lights)
SHTF - Sh*t Hits The Fan (things going seriously wrong - generally used to describe an event that sets society off the rails for some period of time)
SIR - Selective Integrated Rail (see A.R.M.S. website)
SMG - Sub Machine Gun
SMK - Sierra Match King (a hollow tip bullet designed for long range accuracy, made by Sierra Bullets - website)
SNAFU - Situation Normal: All Fouled Up (substitute more colorful adjective for "Fouled" as desired)
SOCOM - Special Operations Command
SOPMOD - Special Operations Peculiar Modification
SOF - Special Operations Forces (in addition to its standard military usage, also a designation for a now discontinued mid-length AR-15 carbine made by ArmaLite)
SP - Soft Point (a bullet whose lead tip is exposed rather than jacketed in a harder metal)
SPC - Special Purpose Cartridge (as in the new 6.8 mm SPC)
SPORTS - Mnemonic for AR-15 immediate action drill: Slap the bottom of the magazine. Pull the charging handle. Observe the open chamber area. Release the charging handle. Tap the forward assist. Shoot. Some people consider this to be remedial action rather than immediate action. See also TRB and TPRRRS.
SPR - Special Purpose Rifle (18" free floating match barrel upper)
SS - Stainless Steel

T - Top (as in the numbered stations on the top rail of an A4 upper)
TCH - Tactical Carry Handle (a specialized carry handle made by RRA and designed to mount Aimpoint red dot sights via Aimpoint's low ring)
TD - TangoDown (manufacturer of grips, both vertical and pistol)
TDP - Technical Data Package (the collection of drawings, engineering notes, etc. that describe in detail the design and construction of an item)
T&E - Test and Evaluation
TPRRRS - Tap, Pull, Rack, Roll, Release, Shoot (an alternative to the traditional SPORTS IAD)
TRB - Tap Rack Bang (an immediate action drill: tap the bottom of the magazine to ensure it is seated, rack the slide, and shoot [bang]. See also SPORTS and TPRRRS)

UBR - Utility/Battle Rifle (a general purpose adjustable stock made by Magpul, with a fixed cheekweld. Successor to the M93B.)
UD - Unintentional Discharge (a weapon discharge made without deliberate or conscious intent, including accidental, involuntary and negligent discharges)
URX - Upper Receiver eXtension (a free-floating rail system made by Knight's Armament)
USGI - United States Government Issue (often in reference to magazines - most regard USGI mags as the best)
USMC - United States Marine Corps

VFG - Vertical Fore/Forward/Front Grip
VLTOR - Ancient Roman spelling for the Latin word ULTOR, meaning "Avenger" (more directly, a modular stock system for the M16, M4 and AR series of rifles)

WOA - White Oak Armament (retailer of AR-15 parts)
WOP - White Oak Precision (builder of custom AR-15 and AR-10 uppers)
WSSM - Winchester Super Short Magnum
WWB - Winchester White Box (In AR-15 context, Q3131A ammunition made in Israel to M193 specifications - relatively inexpensive but reliable general purpose ammo)

XCR - eXchangeable Caliber Rifle* (Robinson Armament's modular battle rifle, originally intended as a SCAR contender)
XM193 - M193 ammunition packaged for sale to civilians (may fail to meet some aspect of military standard)
XM8 - Designation of a modular weapon system that may replace the M16 family of rifles. Adoption of the XM8 is uncertain.

YHM - Yankee Hill Machine (manufacturer of rails, mounts, forearms, sights and other AR-15 accessories)

Z - Zero (marked on some A2-style rear sight elevation knobs to indicate the position at which the knob should be set when establishing a battlesight zero on a 25-meter range according to standard military doctrine)

Edited by TackleberryMCS
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This is really nicely done Tackleberry, appreciate the alphabetized format as well.

I cannot take all of the credit. I used a list that was composed several years ago on another forum and cleaned it up. That took a little while. I took out the stuff that did not pertain and added a few things that did and a couple things for clarification. All in all, this list should be very helpful to everyone here.

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Dear Mr TackleberryMCS,

Sir: Thank you, thank you, thank you. Your post is such a great resource! Now when I encounter weird acronyms, I know that the drive to un-ignorance is only a few clicks away. ( I have to ask: How long did it take you to pull this glossary together??

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Dear Mr TackleberryMCS,

Sir: Thank you, thank you, thank you. Your post is such a great resource! Now when I encounter weird acronyms, I know that the drive to un-ignorance is only a few clicks away. ( I have to ask: How long did it take you to pull this glossary together??

Not that long. There was a list compiled on another forum several years ago. I copied it and had to make several changes to finalize the list you see here. A lot of stuff on the original list was not applicable AR terms and were deleted and there had been some newer terms that I had to add.

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