AR15 Definitions, Acronyms, and Abbreviations

AR15 Definitions, Acronyms, and Abbreviations


A1, A2, A3 etc… Refers to military designations or alterations of various firearms including M16 & M4.

AR – Means ArmaLite right?  There is some debate as to the meaning of AR as the original ArmaLite company designed the AR15 rifle, Colt later has a CAR 15, which was based on the original Eugene Stoner ArmaLite design, however the CAR meant Colt Automatic Rifle.

AWB – Assault Weapons Ban. An infringement on your 2nd Amendment rights is the classifying of what an assault weapon is typically by legislative body (government).

BBL – Barrel.

BCG – Bolt Carrier Group

BDC – Bullet Drop Compensator

BRD – Black Rifle Disease

BUIS – Back Up Iron Sight

CAR – Carbine. A carbine is a medium barrel length rifle, typically with a 16″ long barrel.

Compliant – Typically refers to Ar15′s or parts and accessories which adhere to various infringements, bans or restrictions; such as “California Compliant”.

CQB – Close Quarters Battle.

DC – Dust Cover

DCH – Detachable Carry Handle

DD – Daniel Defense

DD – Destructive Device

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

DIY – Do It Yourself

DPMS – Defense Procurement Manufacturing Services – builder of AR-15 rifles and supplier of parts and accessories

DSA – D.S. Arms

EBR – Evil Black Rifle

ETA – Estimated Time of Arrival

FA – Forward Assist

FA – Full Auto

FAQ – Frequently Asked Questions

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 and/or  transfer guns in interstate commerce.

FH – Flash Hider

FMJ – Full Metal Jacket – a bullet that is encased in a metal jacket.

FMJBT – Full Metal Jacket Boat Tail

FN – Fabrique Nationale

FOIA – Freedom Of Information Act

FP – Firing Pin

FS – Flash Suppressor

FSB – Front Sight Base

FSP – Front Sight Post

FST – Front Sight Tower

FTE – Fail To Eject/Extract

FTEj – Fail To Eject

FTEx – Fail To Extract

FTF – Fail To Feed

LPK – Lower Parts Kits

FSB – Front Sight Base, sometimes called Front Sight Post.

GCA – Gun Control Act of 1968

HBAR – Heavy Barrel

HG – Handguard

HP – Hollow Point (a bullet with a hollow cavity at the tip)

HTS – Hammer, Trigger, Sear (parts of the FCG)

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)

IPSC – International Practical Shooting Confederation (Also See USPSA)

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.

LOP – Length Of Pull – the distance from the face of the trigger to the end of the buttstock.

LPK – Lower Parts Kit

LW – Lightweight

M16 – The original full-auto military version of the AR-15 rifle.

M4 – A 14.5″ barrel carbine version of the M16A2.

MAP – Minimum Advertised Price (A price below which retailers are prohibited from advertising a product. Not all manufacturers/distributors enforce MAP policies, and even when they do, retailers are not legally prohibited from selling below MAP.)

Mil Spec – Military Specification. A United States defense minimum standard, often called a military standard, “MIL-STD”, is used to help achieve standardization objectives. Mil Spec will define shape, size, metallurgy and treatments of a firearm and firearm components. Also see TDP.

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.

MP – proof mark that indicates Magnetic particle inspection and Proof load firing has been performed on a barrel. 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.

MRF – Modular Rail Forend (a rail adapter system made by Troy Industries)

MSRP – Manufacturer’s Suggested Retail Price

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.)

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)

NM – National Match – Sometimes used to describe the 1specified quality of an item. However refers to the National Matches sponsored by the Civilian Marksmanship program.

NSN – National Stock Number  – a unique number assigned to each item in the Federal Supply Cataloging System, including parts and accessories for military weapons.

NVD – Night Vision Device

OAL – Overall Length

OD – Olive Drab. Sometimes called ODG for Olive Drag Green or Army Green.

OD – Outside Diameter

OTM – Open Tip Match – a type of hollow point bullet designed for long range accuracy.

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 compact weapon designed primarily for defensive rather than offensive operations.

POA – Point Of Aim

POI – Point Of Impact

Post ban – Typically referring to AR15′s which adhere to the 1994 Clinton Assault Weapon Ban which has since expired.

Pre ban – Typically referring to AR15′s or parts and components without restriction.

PRS – Precision Rifle/Sniper  – a precision stock made by Magpul, adjustable for height and LOP.

QCB – Quick Change Barrel.

QD – Quick Detach.

RAS – Rail Adapter System.

RDIAS – Registered Drop-In Auto Sear

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

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.

SAW – Squad Automatic Weapon

SBR – Short-Barreled Rifle (a rifle whose barrel is less than 16″ long as defined by the NFA)

SD – Shell Deflector

SMG – Sub Machine Gun

SP – Soft Point – a bullet whose lead tip is exposed rather than jacketed in a harder metal.

SPC – Special Purpose Cartridge as in “6.8 mm SPC”.

SPR – Special Purpose Rifle – precision rifle with 18″ free floating match barrel upper.

SS – Stainless Steel

TDP – Technical Data Package – the collection of drawings, engineering notes, etc. that describe in detail the design and construction of an item.

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)

USGI – United States Government Issue – Usually is used as a reference to magazines.

VFG – Vertical Fore/Forward/Front Grip

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