The Gun Violence Glossary

A

AK-47

The AK-47 is a category of assault rifle invented in Russia at the conclusion of World War II. It has become one of the most popular weapons in the world and is now manufactured in several countries, with several more using it in military service. In the U.S., most models are prohibited because of their full automatic capability, though there are exceptions for units registered before 1986 and models that do not have full automatic capabilities. AK-47s are known for their reliability and ubiquity.

assault rifle

Not to be confused with “assault weapon,” an assault rifle is defined by an intermediate cartridge (one with more power and size than a pistol’s, but less than those intended for higher calibers and longer range), the ability to change firing modes between semiautomatic, full-automatic, and burst, and a detachable magazine. Common examples include the AK-47 and M-16.

Assault Weapons Ban of 1994

The Public Safety and Recreational Firearms Use Protection Act, a subsection of the Violent Crime Control and Law Enforcement Act of 1994, prohibited manufacturing some semiautomatic firearms considered “assault weapons” and certain large-capacity magazines.

ATF

The Bureau of Alcohol, Tobacco, Firearms and Explosives — commonly ATF — is a United States law enforcement agency within the Department of Justice charged with investigation and enforcement surrounding firearms, explosives, arson, bombings, and illegal trafficking and tax evasion of alcohol and tobacco. Previous incarnations were housed in the Department of the Treasury and the Federal Buerau of Investigation. In 2002, with the creation of the Department of Homeland Security, ATF was moved from Treasury to DOJ.

automatic firearm

An automatic, or fully automatic, firearm is characterized by the ability to continuously fire rounds as long as the trigger is depressed. It is differentiated from a semiautomatic firearm, which automatically loads rounds once fired, but still requires a separate trigger pull for each round fired.

B

Brady Handgun Violence Prevention Act

Commonly referred to as the Brady Bill, it’s a 1993 act of Congress introduced by then-U.S. Representative Charles Schumer, a New York Democrat, requiring federally licensed firearm dealers to conduct background checks on gun buyers. Private sales are exempt. The Brady Bill was appended to Title 18, Sec 922 of the U.S. Code.

bullet

The kinetic projectile ejected from a firearm by an explosion of propellant such as gun powder. Bullets are most commonly packaged as part of a cartridge that includes a casing holding the propellant, but can also be separate as in the case of most muzzle-loaded firearms. Also referred to as a “round.”

bump stock

A type of gun stock on a semiautomatic weapon that enables the user to somewhat mimic the output of a fully automatic firearm.

C

caliber

The internal diameter of a gun’s barrel measured in millimeters or inches. In rifled barrels, the dimension can be measured between the grooves of the barrel or to the ridges; in the U.S., measuring between the grooves is more common.

child access prevention law

A law making it illegal for an adult to keep a gun in such a way that a child could access and fire it. In the United States there is no such law at the federal level, though half of states have codified a version of such legislation.

clip

A tool that holds multiple rounds of ammunition for insertion into a magazine or sometimes directly into the firearm. The term is not sysnonymous with magazine.

Colt AR-15

The Colt AR-15 is the successor to the ArmaLite AR-15, itself a successor to the ArmaLite AR-10. In 1977, Colt’s patent expired leading to numerous “AR-15 style” copycat weapons from other manufacturers and a conflation of the AR-15 moniker — a Colt-specific trademark. Colt has made both civilian and law enforcement/military models, the former designed to comply with the assault weapons ban that lasted from 1994 to 2004.

concealed carry

In contrast to open carry, the act of possessing a firearm on one’s person out of public view. Concealed carry is the subject of much debate in firearm regulation and among gun owners.

D

Defensive gun use

Discharging a gun in the face of a perceived threat. Defensive gun use is the primary argument for owning a gun in America today. Self-defense is the reason most often cited by gun buyers.

District of Columbia v. Heller

A 2008 landmark Supreme Court decision that affrimed an individual right to bear arms regardless of service in a militia. The case started in 2002 and took on a District of Columbia law that banned handguns and required long gun owners to keep their firearms unloaded and dissassembled or trigger-locked. The justices noted that the decision did not allow a limitless right to bear arms and that some restrictions on guns and ownership were constitutional.

F

federal firearms license (FFL)

A license issued by the ATF that allows individuals or companies to legally engage in the manufacture, import, and sale of firearms and ammunition. Under the 1993 Brady Act, FFLs are required to conduct background checks on gun buyers at the point of sale.

Firearm Owners Protection Act

A 1986 law drafted by the National Rifle Association that amended much of the Gun Control Act of 1968, including: 1) outlawing the creation of a national gun registry that would link individual owners to firearms, 2) enabling states to exempt felons from a federal ban on gun ownership, 3) increasing gun crime sentences, 4) prohibiting the future manufacture and sale of machine guns for civilians, and 5) heavily curtailing the ATF’s regulatory and enforcement capabilities. It was widely opposed by law enforcement groups and later touted by the NRA as “the law that saved gun rights.” It was signed into law by President Ronald Reagan five years after he survived a shooting.

G

ghost gun

An unserialzied — and therefore untraceable — firearm. A “ghost gun” is considered by law enforcement to be any firearm with a defaced or missing serial number, including guns sold by manufacturers. But ghost guns are increasingly assembled by users from pre-made kits or made in a 3D printer.

Gun Control Act of 1968

Legislation sparked by the 1960s-era assassinations of President John F. Kennedy, Attorney General Robert F. Kennedy, and the Reverend Dr. Martin Luther King Jr. that imposed stricter licensing and regulation on the firearms industry and prohibited the sale of firearms and ammunition to felons and other prohibited persons. The act has been heavily modified by subsequent legislation but current features are codified in 26 U.S. Code § 5801.

gun show loophole

A general term that describes limitations of the 1993 Brady Handgun Violence Prevention Act that established background checks on gun buyers, but exempted sales at gun shows and yard sales, between friends and strangers, or arranged through online listing sites such as Armslist and GunBroker. Commonly referred to as the private sales loophole.

H

handgun

A firearm designed to be used with one hand, as opposed to a long gun designed for use with two hands and typically braced against the shoulder. They are usually more portable, less powerful, and less accurate than a long-barreled gun. Handguns are the most common type of firearm used in crime — including mass shootings.

high-capacity magazine

A firearm magazine that can hold a large number of rounds. Legally, exact numbers vary from state to state. The Federal Assault Weapons Ban of 1994-2004 restricted magazines containing more than 10 rounds.

hospital-based violence intervention program (HVIP)

A form of community violence intervention that provides holistic, rehabilitative treatment to patients suffering from gunshot wounds while mitigating reinjury or potential retaliation. Medical staff connect shooting victims to violence intervention specialists from their communities, who provide emotional support to address trauma and help them navigate available resources as they adjust back to daily life.

I

Iron Pipeline

A notorious gun trafficking route so named by the ATF that runs from Florida to New England, where guns sold in the South are transported to Northern states.

M

machine gun

A gun that enables continuous firing so long as the trigger is depressed. According to U.S. Code: The term “machine gun” means any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically, more than one shot, without manual reloading, by a single function of the trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machine gun, and any combination of parts from which a machine gun can be assembled if such parts are in the possession or under the control of a person. (26 U.S.C. § 5845(b))

magazine

An ammunition storage device designed to repeatedly feed rounds into the chamber of a firearm. The term is not synonymous with clip, which is an ammunition storage device that lacks the feeding capability of a magazine. Clips often feed into magazines.

mass murder / mass killing / mass shooting

A collection of terms with no single definition, legal or otherwise, that refer to an event including multiple fatalities or other casualities. For example, the Department of Justice has characterized mass shootings as “any incident in which at least four people are murdered with a gun.” The Gun Violence Archive defines mass shooting as an event where “a minimum of four victims shot, either injured or killed, not including any shooter who may also have been killed or injured in the incident.”

N

National Firearms Act

The 1934 federal law that regulates machine guns. Passed in the wake of several high-profile early 20th century shootings, particularly involving the Thompson submachine “Tommy” gun, the NFA imposes a tax-and-registration system on purchasers of machine guns, silencers, and short-barreled rifles and shotguns. You must be fingerprinted and photographed, go through a background check, have your weapon registered, and pay a $200 fee. Given that NFA-regulated firearms are rarely found at crime scenes, the NFA is considered one of the most successful gun control laws in U.S. history.

National Instant Criminal Background Check System (NICS)

The national background check system required by the 1993 Brady Act, which went online in 1998 and is managed by the Federal Bureau of Investigation. While the bureau manages the system, its involvement in the actual checks varies from state to state, with some accessing the database on their own and others dividing management between handguns and long guns.

National Rifle Association

A gun rights advocacy group in the United States founded in 1871 to promote and enhance rifle aim and practice. The organization did not formalize its political activity until the passage of the National Firearms Act in 1934 and remained largely nonpartisan until the 1970s, when under Harlon Carter the group’s conservative political influence actions ballooned. In February 2024, the group’s leaders were found guilty of financial misconduct and corruption.

New York State Rifle & Pistol Association, Inc. v. Bruen

A 2022 landmark Supreme Court decision that codified the right to carry a gun outside the home for self-defense. It also rewrote the methodology for deciding whether gun laws are constitutional, imposing a “history and tradition” test and removing public safety considerations. Locally, the decision eliminated a requirement in New York and 7 other states that a gun permit applicant demonstrate “good cause” for carrying a firearm.

O

open carry

Visibly carrying a firearm in public, as opposed to concealed carry where the weapon is hidden from public view.

P

permitless carry

A policy adopted by 29 states that allows residents to carry a concealed handgun without licensing or training.

R

red flag law

Legislation that gives judges the authority to temporarily remove guns from people deemed to be a danger to themselves through what’s known as an “extreme risk protection order.” It’s a civil, not criminal, process and does not result in the permanent loss of gun rights.

S

Second Amendment

The second entry in the Bill of Rights that reads: “A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.” Throughout American history, the Second Amendment was legally understood to describe a collective, not individual, right to bear arms, but that changed with the 2008 Supreme Court decision District of Columbia v. Heller, which established an individual right to keep and bear arms for self-defense.

semi-automatic firearm

A gun that fires a single round when the trigger is pulled and a second bullet is loaded into the firing chamber.

Stand Your Ground

A self-defense law adopted by 30 states that allows gun owners to use deadly force in public and relieves them of the duty to retreat.

T

Tiahrt Amendment

A 2003 Congressional appropriations rider that prohibits the ATF from releasing information about crime guns to the public. Tiahrt also requires the FBI to destroy all successful background check records within 24 hours and prohibits the ATF from requiring gun dealers to submit their inventories to law enforcement while they’re still in business.

trace

A gun trace, typically conducted by law enforcement on a firearm found at a crime scene, that aims to source the gun to its original buyer and most recent owner.

U

universal background checks

A policy adopted by 20 states that requires background checks with all gun sales. Federal law requires background checks only on sales of guns through federally licensed dealers and permits private sales between friends, strangers, and family members, as well as at gun shows and via the internet.