Is most active shooting crimes committed by illegal (unlicensed) gun/firearms?

Question

I am trying to do a research on gun. Then this important question came to my mind. But I couldn't found the answer anywhere. I need static percentage with the sources please.

Answer 1

Hi Jack,

This is a great question, and the short answer is:

Yes — most gun crimes in the U.S., including many active shootings, are committed with illegally possessed or unlawfully carried firearms.

However, the exact percentage depends on which category of violence you are looking at (general gun crime, homicide, mass shootings, or “active shooter” events specifically).

Below are the most reliable data points currently available:

1. General Gun Crimes (All Violent Firearm Offenses)

According to the U.S. Department of Justice (DOJ), Bureau of Justice Statistics (BJS), and the 2016 Federal Firearm Offenders Study, the following is true:

1. 90% of guns used in federal gun crimes were not obtained legally by the offender.

Most were:

1. Stolen
2. Bought on the street
3. Obtained through straw purchasers
4. Acquired through underground markets

This DOJ study is one of the strongest pieces of evidence showing that the vast majority of everyday gun crimes involve illegal possession.

2. State-Level Police Data on Crime Guns

According to the Chicago Police / ATF Firearm Trace Data:

1. Over 90% of guns recovered from crime scenes in Chicago were illegally possessed (no valid FOID card, not registered, or purchased out of state).
2. 60% of these guns were trafficked from outside Illinois.

Other cities with available data (Baltimore, NYC, Los Angeles) show similar patterns: most crime guns are not legally owned by the offender.

3. Homicides Involving Firearms

According to the Bureau of Justice Statistics (BJS) and “Firearm Violence, 1993–2011”

1. About 77% of homicide offenders were prohibited possessors at the time (prior felony convictions, restraining orders, etc.)
2. These individuals cannot legally purchase or carry firearms — meaning the guns used were obtained illegally.

4. Mass Shootings vs. Active Shooter Events

This distinction is important. Mass Shootings are defined as follows: 4+ people killed, excluding the shooter.

According to Everytown, Mother Jones database, and FBI case files

1. Most mass shooters acquire guns legally, because they typically do not have felony records or disqualifying conditions.
2. Estimated ~77–85% use legally purchased firearms.

Active Shooter Incidents are defined by the FBI as follows: individual(s) actively attempting to kill people in a populated area

1. Many active shooters also purchased guns legally, not illegally.
2. Motivations often differ from general gun crime offenders (terrorism, workplace grievance, school shootings, etc.).

5. Summary of the Best Available Evidence

Category of Gun Violence	% Illegal Guns	Notes
General firearm crime	~90% illegal	Strong DOJ/FBI support
Homicides	~77% illegal	Offenders typically prohibit possessors
Mass shootings	Mostly legal guns	Shooters often have no criminal history
Active shooter incidents	Mixed, but many legal guns	Different motivation pattern

Conclusion

1. If the question is “Are most gun crimes committed with illegal firearms?”

→ Yes, overwhelmingly (~75–90%).

1. If the question is “Are most active shooter events committed with illegal firearms?”

→ No. Many active shooters use guns purchased legally.

Different types of violence involve different offender profiles and different firearm acquisition patterns.

If you’d like, I can provide direct links to each government report or help you break this down into a research paper format.