Chicago Sues Glock, Points to 3D Printing in Gun Modifications

Chicago is stepping up its fight against gun violence by expanding a major lawsuit against Glock. The city isn’t just going after the gun manufacturer anymore—now it’s targeting Glock’s parent company in Austria, Glock Ges.m.b.H, and two local gun shops that sell these firearms, Eagle Sports Range and Midwest Sporting Goods.

At the heart of this lawsuit is the alarming rise of illegal modifications made possible by 3D printed devices, known as “Glock switches,” which can transform semi-automatic pistols into fully automatic machine guns. Chicago claims that Glock is making it too easy for criminals to turn its pistols into illegal machine guns with a cheap and simple device, fueling violence on the city’s streets. The city is also accusing the gun dealers of irresponsibly selling Glock pistols despite knowing the risks associated with their easy modification.

Glock-style auto sears can be attached to the back of pistols, as seen in the image of a Modified Glock. Image courtesy of the City of Chicago.

Glock pistols have become a particular preference by people seeking to convert them into fully automatic weapons. The complaint alleges that from 2021 to May 2024, over 1,300 modified Glocks were recovered by the Chicago Police Department, averaging more than one per day. These modified weapons that use “Glock switches” can fire up to 1,200 rounds per minute—a faster rate of fire than the standard M4 machine gun used by the United States military. According to a newly expanded complaint filed on July 22, 2024, this modification makes them extremely dangerous and difficult to control, often resulting in more casualties during shootings.

“An untrained shooter using an unmodified semiautomatic Glock may already have a difficult time maintaining the gun’s recoil to stay on target while firing. That problem is exponentially greater when firing a modified Glock. It is much more difficult for shooters to manage a modified Glock’s recoil and maintain their target when firing so many rounds in rapid succession, resulting in more lethal shootings, grievous wounds for survivors, and greatly enhanced risks for bystanders,” states the document.

For example, in a recent federal complaint filed against an accused auto sear trafficker, the city of Chicago says that the defendant “bragged that his auto sears were compatible with a Gen5 Glock and could make it fire 30 rounds in two seconds.”

Interestingly, a company that uses audio sensors to monitor gunfire reported that there were 75,544 recorded rounds of “suspected automatic gunfire in 2022 in portions of 127 cities covered by its microphones,” including Chicago, representing “a 49% increase from the year before.” According to law enforcement, this increase is attributable, in part, to fully automatic pistols being seen by teenagers as “status symbols that provide a competitive advantage.”

Auto sears, small devices that turn semi-automatic pistols into fully automatic weapons, are often made using 3D printing technology in the United States. These devices are cheap, sometimes costing as little as $20, and are frequently marketed online under false labels. Many auto sears are produced from downloadable CAD files, making them difficult for authorities to track and stop. Moreover, Chicago argues that the “ease of 3D printing these parts is fueling their spread in the criminal market,” making it even harder to crack down on their illegal use.

An auto sear affixed with a Glock logo. Image courtesy of the City of Chicago.

The City of Chicago claims that Glock has been aware of this issue for years but has failed to make simple design changes that could prevent these modifications. Instead, the lawsuit filings state that the company allegedly continues to profit from sales of its easily modified pistols. The lawsuit also accuses Glock of promoting its products through “dealers that have a track record of violating federal gun laws and disproportionately supplying criminals with the guns they use in crimes all over Chicago.”

One of the key arguments in the lawsuit is that modifying other popular pistols, like those made by Smith & Wesson or Sig Sauer, requires time-consuming and difficult engineering, whereas modifying a Glock pistol is relatively simple. Videos demonstrating how to convert a Glock into a fully automatic weapon are widely available online, contributing to the growing trend of modified Glocks.

The lawsuit also details several incidents in which modified Glocks were used in violent crimes across Chicago, including shootings in residential neighborhoods, drive-by shootings, and gang-related violence. The complaint also highlights that many of these modified weapons are found in the hands of minors.

One of the defendants, Eagle Sports Range, is particularly accused of marketing modified Glocks as part of its “full auto experience,” allowing customers to rent and fire machine guns at its indoor range. Despite having its federal firearms license revoked by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) in 2022 for multiple violations, the store allegedly continued operations under a new entity run by a relative of the original owner.

Glock designed its civilian-purchased pistols to be easily modified. Image courtesy of the City of Chicago.

Chicago wants Glock to stop selling pistols that can be easily turned into machine guns and to quit “misleading” people about the dangers of these firearms. The city is also pushing for daily fines against Glock and its partners as long as they keep breaking the law.

This lawsuit is part of Chicago’s ongoing efforts to tackle the growing gun violence in the city. Although the outcome is still uncertain, the case draws attention to the ongoing debate about gun control, the responsibilities of gun makers, and the use of 3D printing to modify weapons.

Chicago’s lawsuit against Glock is a big legal challenge for the gun industry. It points to how easily some pistols can be turned into illegal machine guns using 3D printing. However, this situation also makes things harder for people in the 3D printing community who use the technology for legal and recreational purposes. The spotlight on 3D printing here focuses on its connection to criminal activities involving gun modifications, adding extra scrutiny to the entire community.