2A Glossary

2A

Second Amendment

Shorthand for the Second Amendment. Someone who is "pro-2A" supports gun rights.

3-Gun

Competitions shot with pistol, rifle and shotgun in the same match.

80% Receiver

Unfinished Receiver

An unfinished frame or receiver that still needs machining to work. Since ATF’s 2022 rule, many of these parts and kits count as firearms under federal law, with serial numbers and background checks; the Supreme Court upheld that rule in 2025 (Bondi v. VanDerStok). New York and New Jersey ban unserialized frames, receivers and the guns built from them.

613

The traditional count of commandments (mitzvos) in the Torah. It is how this site refers to the Orthodox Jewish community: everything 2A, for the 613 community.

A Good Guy with a Gun

The phrase for an armed citizen who stops an attacker.

Action

The working parts of a gun that load, fire and unload.

Affirm / Reverse

The appeals court agrees with the lower court (affirm) or overturns it (reverse).

AIWB

Appendix Inside the Waistband

Inside-the-waistband carry at the front of the body.

AK

Avtomat Kalashnikova

The rifle family based on the Soviet Kalashnikov design.

Amicus Brief

Friend of the Court Brief

A brief filed by an outside group with an interest in the outcome. Gun cases attract many.

An Armed Society Is a Polite Society

A Robert Heinlein quote gun owners love to cite.

Ankle Holster

A holster strapped above the ankle, usually for a backup gun.

Antonyuk

The federal lawsuit challenging New York’s post-Bruen carry law.

AOW

Any Other Weapon

The NFA’s catch-all category for unusual items, like guns disguised as other objects.

Appeal

Asking a higher court to review a lower court’s decision.

Appleseed

Project Appleseed

A volunteer-run rifle marksmanship program taught across the country.

As-Applied Challenge

Arguing a law is unconstitutional as enforced against this particular person.

Assault Weapon

A legal category defined by each state’s law, not a technical term. New York’s law covers semi-automatic rifles that take a detachable magazine and have at least one listed feature, such as a pistol grip, a folding stock or a threaded barrel. New Jersey uses a list of named models plus a similar features test. Many gun owners dispute the label.

ATF

Bureau of Alcohol, Tobacco, Firearms and Explosives

The federal agency that regulates gun dealers and enforces federal gun laws.

AWB

Assault Weapons Ban

A law banning so-called assault weapons. The federal ban ran from 1994 to 2004; some states have their own.

Background Check

The criminal and mental-health records check run before a gun sale. When and how it runs depends on federal and state law.

Ballistics

The study of projectiles in flight: internal (in the gun), external (in the air) and terminal (on impact).

Behind Enemy Lines

Lighthearted slang for living in a state with strict gun laws.

BNIB / NIB

Brand New in Box / New in Box

Listing shorthand for unused items in original packaging.

Boating Accident

A long-running joke about having "lost" all of one’s guns in a boating accident. It is only humor, not advice.

Bolt-Action

Cycled by lifting and pulling a bolt. Common for hunting and precision rifles.

Brady Act

The 1993 law that created the federal background check requirement.

Break-Action

Opens on a hinge to load, like most double-barrel shotguns.

Brief

A written legal argument filed with the court.

Bruen

NYSRPA v. Bruen

The 2022 Supreme Court decision that struck down New York’s "proper cause" requirement and confirmed the right to carry in public for self-defense.

BUG

Backup Gun

The small second gun some carriers carry.

Build

A gun you assembled yourself from parts, as in "my first build."

BUIS

Backup Iron Sights

Sights kept ready in case an optic fails.

Bullpup

A design with the action and magazine behind the trigger, making the gun shorter overall.

Bump / BTT

Bump to Top

Replying to your own forum listing to push it back to the top.

C&R License

Curio and Relic License, the "03 FFL"

A collector’s license for old and historical firearms.

Caliber Wars

The endless debate over which cartridge is best, classically 9mm versus .45.

Cant

The angle a holster tilts the gun.

Capacity

How many rounds a magazine holds. Some states limit this by law.

Carbine

A short, light rifle.

Castle Doctrine

The idea that you have no duty to retreat when attacked in your own home. The details vary by state.

CCIA

Concealed Carry Improvement Act

New York’s 2022 gun law passed after Bruen. It added training and location rules for carry permits, and many of its provisions have been challenged in court.

CCW

Carrying a Concealed Weapon

In many states this is the name of the permit itself: "getting your CCW" means getting your concealed-carry license.

Ceasefire

The command to stop shooting immediately, unload and step back from the line.

Certiorari

Cert

The way a losing side asks the Supreme Court to review a case. "Cert granted" means the Court will hear it. "Cert denied" means it declined to review, which is not an endorsement of the decision below.

CHL / CHP / CWP

Concealed Handgun License, Concealed Handgun Permit, Concealed Weapons Permit

Other states’ names for a carry license.

Circuit Court

Court of Appeals

The federal appeals level, mostly organized in numbered regional circuits. New York sits in the Second Circuit.

Class Action

One lawsuit brought on behalf of a whole group of people in the same situation.

Claw / Wing

A holster attachment that pushes the grip toward the body to hide it better.

CLEO

Chief Law Enforcement Officer

The local police chief or sheriff; older NFA applications needed a CLEO sign-off.

Clone

A gun built to replicate a military-issue configuration.

CMP

Civilian Marksmanship Program

The federally chartered program that runs marksmanship training and matches.

Co-Witness

When iron sights line up through an optic as a backup.

Come and Take It

The slogan on the 1835 Gonzales cannon flag from the Texas Revolution. The Texas cousin of molon labe.

Complaint

The document that opens a lawsuit and lays out the claims.

Concealed Carry

Carrying a handgun hidden from view, which is what carry permits cover.

Concurring Opinion

Agrees with the outcome of the case, sometimes adding or substituting different reasoning.

Constitutional Carry

Permitless Carry

When a state lets legally eligible adults carry a firearm without a permit. Many states have adopted some version of it; whether yours has is worth checking.

Cover Garment

The overshirt or jacket that hides a carry gun.

CPL

Concealed Pistol License

Michigan’s and Washington’s name for a carry license.

Cross-Draw

Carrying on the opposite hip, drawn across the body.

Decocker

A lever that lowers the hammer without firing.

Deep Concealment

Gear and methods for carrying where detection matters most.

Defendant

The side being sued.

Derringer

A very small pistol, usually holding one or two shots.

Destructive Device

The NFA category for explosives and very large-bore weapons.

Dissent

A judge’s written disagreement with the majority.

District Court

The federal trial court, where federal lawsuits start.

Docket

The court’s official list of everything filed and scheduled in a case.

Downrange

The direction toward the targets.

Drop-Leg / Thigh Rig

A holster on a panel strapped to the thigh.

Dry Fire

Practicing with an unloaded gun: aim and trigger press with no ammunition.

Duty to Inform

A rule in some places requiring you to tell a police officer you are carrying during a stop. Whether and when it applies depends on the jurisdiction and the circumstances, so check the rule where you carry.

eForms

The ATF’s online filing system for NFA paperwork.

En Banc

When the full appeals court, or a larger authorized group of its judges, hears a case instead of the usual three-judge panel. Usually reserved for big ones.

Extractor / Ejector

The parts that pull out and kick out a spent case.

Facial Challenge

Arguing a law is unconstitutional in every application.

FFL

Federal Firearms License

The federal license that gun stores and dealers need to sell firearms. Online gun purchases are shipped to a local FFL, who handles the legal transfer.

FID

Firearms Purchaser Identification Card

New Jersey’s name for the card you need before buying rifles or shotguns.

Firing Line

The line shooters stand behind. No one goes past it while shooting is live.

First Circuit

The federal appeals court covering Maine, Massachusetts, New Hampshire, Puerto Rico and Rhode Island.

Flair

The label next to a username on a forum, often showing location or permit status.

FOID

Firearm Owner’s Identification

Illinois’s version of an owner ID card, needed there for guns and ammunition.

Foot-Pounds (ft-lbs)

How bullet energy is measured.

FOPA

Firearm Owners Protection Act

The 1986 law that eased some GCA rules and closed the machine gun registry to new entries.

Form 1

The ATF application to make and register an NFA item.

Form 4

The ATF application to transfer an NFA item.

FPC

Firearms Policy Coalition

A gun-rights group active in litigation.

FPS

Feet Per Second

How bullet speed is measured. Muzzle velocity is the speed as the bullet leaves the barrel.

Frangible

Ammunition designed to break apart on hard surfaces, required at some ranges.

Free State / Ban State

Casual forum shorthand for states seen as friendly or hostile to gun owners.

From My Cold Dead Hands

Charlton Heston’s famous NRA rally line. Shorthand for never giving up one’s guns.

FTF

Face to Face

An in-person deal, as in "FTF only." Elsewhere the same letters mean failure to feed or fire.

FWIW

For What It’s Worth

A softener before offering a thought.

GAFS

Gun Accessories For Sale

A big online community where members list used gear.

GCA

Gun Control Act of 1968

The backbone of federal gun law: dealer licensing, prohibited persons and interstate sale rules.

Ghost Gun

A privately made firearm with no serial number, often built from a kit or 3D-printed. New York and New Jersey make it a crime to possess one. Many gun owners consider the term loaded.

GOA

Gun Owners of America

A gun-rights organization known for a no-compromise stance.

Grail Gun

The dream gun someone hunts for years.

Grain (gr)

The unit used for bullet weight. Ammo boxes say things like "115 gr" or "124 gr."

Gun Show

A market event where dealers and collectors display and sell. The same laws apply there as anywhere else.

Gun Show Loophole

The political phrase for private sales that skip background checks where state law allows.

Gun Trust

NFA Trust

A legal trust that can hold federally regulated items so more than one named person can lawfully possess them.

Gun-Free Zone

A posted area where guns are banned. Pro-2A folks argue such signs only stop the law-abiding.

gun.deals

A popular site that collects gun and ammo deals from many retailers into one feed.

Gunsmith

A professional who repairs, maintains and works on guns.

Hammer

The part that swings to strike the firing pin in hammer-fired guns.

Handguard

The covering around a rifle’s barrel that you hold.

Handgun

A gun designed to be fired with one hand: pistols and revolvers.

Heller

D.C. v. Heller

The 2008 Supreme Court case confirming the Second Amendment protects an individual right.

Holographic Sight

A non-magnifying optic that projects a hologram reticle.

Hot Range / Cold Range

A range where guns stay loaded between strings (hot) or must be unloaded and racked (cold).

IANAL

I Am Not a Lawyer

The disclaimer people add when they share legal-ish opinions online, to say up front that they are not a lawyer.

IDPA

International Defensive Pistol Association

A shooting sport built around self-defense scenarios with carry gear.

IMO / IMHO

In My (Humble) Opinion

Signals that what follows is a personal take.

Injunction

A court order stopping a law or action from being enforced.

IPSC

International Practical Shooting Confederation

The worldwide body behind practical shooting; USPSA is its US region.

IR Laser / Illuminator

Infrared aiming light that is only visible through night vision.

KaBoom

KB

Slang for a catastrophic gun failure, usually blamed on bad or overloaded ammunition.

Lane

Your assigned shooting position at a range.

Legal Protection Plan

A membership that helps with legal costs after a self-defense incident.

LEO

Law Enforcement Officer

The standard shorthand in any discussion about police encounters.

Levels of Scrutiny

How hard a court looks at a law: strict scrutiny, intermediate scrutiny and rational basis, from toughest to easiest for the government.

Lever-Action

Cycled by a lever under the receiver. The cowboy-movie rifle.

LGS

Local Gun Store

"Check your LGS" is the standard answer to half of all gear questions.

Live Fire

Shooting real ammunition, the opposite of dry fire.

LNIB

Like New in Box

Listing shorthand for barely used with packaging.

LTC

License to Carry

What Massachusetts and Texas call their carry license.

Machine Gun

A firearm that keeps firing while the trigger is held. Private ownership is tightly restricted under federal law.

Majority Opinion

The opinion that speaks for the court.

Malfunction

Any stoppage. "Failure to feed" and "failure to eject" are the usual suspects.

Manual Safety

A switch or lever that blocks the gun from firing.

MAP

Minimum Advertised Price

The lowest price a manufacturer lets a retailer advertise, which is why some prices hide until checkout.

May-Issue

A system where officials could deny a permit even to an applicant who met every objective requirement, for example by demanding a special reason to carry. The Supreme Court’s 2022 Bruen decision struck down New York’s "proper cause" rule. New York still reviews each applicant for "good moral character," which leaves officials some discretion.

McDonald

McDonald v. Chicago

The 2010 case applying the Second Amendment to state and local governments.

Megathread

One big pinned thread where a recurring topic lives.

Micro-Compact

A very small double-stack 9mm pistol, the popular carry size of recent years.

Militia

The "well regulated Militia" named in the Second Amendment’s opening clause.

MOA

Minute of Angle

An angular measure used for accuracy, about one inch at 100 yards. "One MOA" means inch-sized groups at that distance.

Molon Labe

Greek for "come and take them," a defiant phrase attributed to King Leonidas of Sparta. You will see it on patches, stickers and shirts.

Motion to Dismiss

A request to throw a case out early, before trial.

MSR

Modern Sporting Rifle

The industry term for semi-automatic rifles fed from a detachable magazine, such as ARs and AKs.

MSRP

Manufacturer’s Suggested Retail Price

The sticker price nobody actually pays.

Muzzle Discipline

Keeping the muzzle pointed in a safe direction at all times.

NATO Spec

Military-standard ammunition dimensions and pressure, marked like "5.56 NATO."

NFA

National Firearms Act

The 1934 federal law covering machine guns, short-barreled rifles and shotguns, and suppressors. It adds federal application, registration and tax requirements.

NICS

National Instant Criminal Background Check System

The FBI system dealers check before transferring a firearm.

NODs

Night Observation Devices

Slang for night-vision goggles.

NRA

National Rifle Association

The country’s best-known gun-rights organization; it also runs a large share of firearms training.

Off-Body Carry

Carrying in a bag or purse instead of on the waist.

OOS

Out of Stock

"Back in stock" and "OOS" fill every deals thread.

OP

Original Poster / Original Post

The person who started the thread, or the first post itself.

Open Carry

Carrying a firearm visibly, not concealed. Whether it is allowed depends entirely on the state.

Oral Argument

The live session where lawyers answer the judges’ questions.

+P

Ammunition loaded to higher-than-standard pressure for more power.

Panel

The usual group of three appeals judges who hear a case.

PCC

Pistol-Caliber Carbine

A rifle-sized gun chambered in a handgun round like 9mm.

Petitioner / Respondent

At the appeals and Supreme Court level: the side asking for review, and the side answering.

Pew Pew

Playful internet slang for guns or shooting.

Pistol Purchase Permit

In New Jersey, a permit needed for each handgun purchase, on top of the FID card.

Plaintiff

The side that brings a lawsuit.

PLCAA

Protection of Lawful Commerce in Arms Act

The 2005 law shielding gun makers from most lawsuits over criminal misuse of their products.

PM / DM

Private Message / Direct Message

"Take it to DMs" means continue privately.

Preemption

When a higher level of government’s law overrides local gun laws.

Preliminary Injunction

An early injunction granted while a case is still being fought.

Premises Permit

New York City’s name for a handgun license tied to keeping the gun at the listed address, as opposed to a carry license.

Printing

When the outline of a concealed gun shows through clothing.

Prism Sight

A compact optic using a prism instead of lenses; the reticle stays visible even without a battery.

Private Sale

A sale between two individuals rather than through a dealer. The rules for it vary by state.

Pro-2A

Supportive of the Second Amendment and gun rights.

Proceed / Delay / Deny

The three possible background-check answers: proceed, delay (more time needed) or deny.

Prohibited Person

Someone federal law bars from possessing guns, such as a convicted felon.

Proper Cause

The old New York requirement to show a special need for a carry license, thrown out by Bruen.

PRS

Precision Rifle Series

The popular long-range precision rifle competition circuit.

PSA

Two meanings in gun spaces: "public service announcement," and Palmetto State Armory, the budget gun and parts retailer.

PTC

Permit to Carry

New Jersey’s name for its carry permit.

Pump-Action

Cycled by sliding the fore-end back and forth. The classic shotgun action.

Rail

The mounting slots on a gun for optics and accessories.

Range

A facility for legal target shooting.

Range Toy

A gun bought for fun at the range rather than for carry.

Receiver

The core body of a rifle. Legally, it is the part that counts as the firearm.

Recertification

A periodic re-confirmation of license-holder information that some states, including New York, require.

Reciprocity

When one state honors another state’s carry permit. Which permits are honored where changes, so check before traveling.

Red Flag Law / ERPO

Extreme Risk Protection Order

A court order temporarily removing guns from someone found to be a danger to themselves or others.

Reloads / Handloads

Ammunition assembled at home from components.

Remand

To send a case back down to the lower court for another look.

Responsible Person

Anyone named in a gun trust who must submit fingerprints and photos with an NFA application.

Restricted Locations

Under New York’s 2022 law, private property where carrying is banned unless the owner posts a sign or gives permission. The federal appeals court has blocked this rule for private property that is open to the public, so check the current status. See also Sensitive Locations.

Retention

How securely a holster holds the gun. "Level II" and "Level III" describe holsters with extra locking mechanisms.

Rifle

A long gun with a rifled barrel, designed to be fired from the shoulder.

RKBA

Right to Keep and Bear Arms

The phrase people use when they talk about gun ownership as a constitutional right.

RSO

Range Safety Officer

The staff member in charge of safety on the firing line.

Ruling / Holding

What the court decided. The holding is the legally binding core of it.

SA/DA

Single-Action / Double-Action

How much work the trigger does: single-action only releases the hammer; double-action cocks and releases it. Some guns switch between the two.

SAAMI

Sporting Arms and Ammunition Manufacturers’ Institute

The industry body that sets commercial ammunition standards.

SAF

Second Amendment Foundation

A gun-rights group focused on court challenges.

SAFE Act

NY Secure Ammunition and Firearms Enforcement Act

New York’s 2013 gun law, which added an "assault weapon" ban, magazine restrictions and tighter permit rules.

Safe Queen

A gun that never gets shot, just admired in the safe.

SBR

Short-Barreled Rifle

A rifle with a barrel under 16 inches, covered by the NFA.

SBS

Short-Barreled Shotgun

A shotgun with a barrel under 18 inches, covered by the NFA.

SCOTUS

Supreme Court of the United States

The highest court in the country, and the final word on federal gun cases.

Second Amendment

The part of the U.S. Bill of Rights that protects "the right of the people to keep and bear Arms."

Second Amendment Sanctuary

A county or state that declares it will not enforce certain gun laws.

Second Circuit

The federal appeals court covering New York, Connecticut and Vermont. It sits in New York City.

Semi-Automatic

Fires one round per trigger pull and loads the next one automatically. Most modern handguns and many rifles work this way.

Sensitive Locations

Places a state designates as off-limits for firearms even for permit holders. New York’s list was created by its 2022 law and has been fought over in court, so the current rules may differ from the original ones.

Shall Not Be Infringed

The closing words of the Second Amendment, often quoted on their own to say gun rights should not be restricted.

Shall-Issue

A system where the state must give you the permit once you meet the objective requirements.

Shoulder Holster

A harness holster worn under the arm.

Snubnose

A revolver with a very short barrel.

SOT / Class 3

Special Occupational Taxpayer

A dealer licensed to handle NFA items. People call them "Class 3 dealers."

SPF

Sold Pending Funds

A listing claimed but not yet paid for.

Stand Your Ground

Laws that remove the duty to retreat outside the home. Whether your state has one, and how far it goes, varies.

Standing

The requirement that the person suing is actually affected by the law. No standing, no case.

Stay

A pause on a ruling or order while appeals continue. "Stayed" means on hold.

Steel Challenge

A speed-shooting sport: five steel targets, best runs count.

Sticky

A post pinned to the top of a forum by moderators.

Straw Purchase

Buying a gun for someone who cannot, or does not want to, buy it themselves. It is a federal crime.

Striker-Fired

The most common modern pistol design, with an internal striker instead of a hammer. Glocks and similar pistols are striker-fired.

Strong-Side Carry

Carrying on your dominant-hand side.

Sub

Short for a topic community on an online forum.

Summary Judgment

A ruling without a trial, when the facts are not genuinely disputed.

Tax Stamp

Proof of the federal tax paid with an NFA application. The amounts and rules have changed over the years, so check current ATF guidance for what applies now.

Text, History and Tradition

The test Bruen set for gun laws: does the law fit the Second Amendment’s text and the country’s historical tradition of regulation?

The 18-Hour Class

16+2

What everyone calls New York’s concealed-carry training course: 16 hours of classroom plus 2 hours of live fire, introduced by the state’s 2022 law.

The Four Rules

The universal gun-safety rules: treat every gun as loaded; never point it at anything you are not willing to destroy; keep your finger off the trigger until ready to shoot; know your target and what is beyond it.

TIL

Today I Learned

Introduces a fact the poster just discovered.

TL;DR

Too Long; Didn’t Read

A one-line summary of a long post.

Trigger Discipline

The safety habit of keeping your finger off the trigger until you are ready to shoot.

TRO

Temporary Restraining Order

A very short-term order to hold things in place until the court can hear the arguments.

Truck Gun

A gun kept in the vehicle. Legality varies by state.

Twist Rate

How fast the rifling spins the bullet, written like 1:7 for one full turn in seven inches.

Type 01 FFL

The standard dealer and gunsmith license.

Type 07 FFL

The manufacturer’s license, which also covers making ammunition.

Universal Background Checks

The policy idea of requiring background checks on private sales too. States differ widely on it.

Uphold

To leave a law or ruling in effect.

UPIN

Unique Personal Identification Number

A number the FBI can issue to buyers repeatedly delayed by mistaken identity.

Upper / Lower Receiver

The two halves of an AR-pattern rifle. The lower carries the serial number.

USCCA

U.S. Concealed Carry Association

A membership organization offering training and legal-protection plans for people who carry.

USPSA

United States Practical Shooting Association

The main American practical-shooting sport: scored courses with movement.

Vacate

To wipe out a lower ruling as if it never happened.

Well Regulated

In 1791 English, "in good working order." The phrase at the heart of arguments over the Second Amendment’s militia clause.

When Seconds Count, the Police Are Minutes Away

The saying behind armed self-defense: you are your own first responder.

WTS / WTB / WTT

Want to Sell / Buy / Trade

The standard prefixes on forum marketplace listings.

YMMV

Your Mileage May Vary

"It worked for me, but your result may differ."