California lawmakers must prevent the sale of DIY machine guns | Opinion

Machine guns have been illegal for decades. But what if, in a matter of moments, a handgun could be transformed into a weapon that fires up to 20 bullets per second? That is now the horrifying reality confronting outgunned police departments and terrorizing communities throughout California and across the nation.

So-called machine gun conversion devices are fueling a surge in gun violence fatalities. Victims range from police officers to young children struck in a barrage of bullets following a single trigger pull.

It is amazing that a device so small and inexpensive can wreak such havoc, and it is extraordinary to see a gun affixed with one in action. Roughly the size of a quarter and readily available for $20 or less, machine gun conversion devices are simple to attach to the backs of some semiautomatic pistols. (They are sometimes referred to as “Glock switches” because they are especially easy to attach to Glock pistols.)

A machine gun conversion device interrupts the gun’s normal firing action, enabling a nearly instantaneous hail of bullets with just one pull of the trigger.

Because a gun equipped with an this device fires so many rounds so rapidly, it renders the firearm difficult for even trained experts to control. Bullets fly everywhere. As a result, shootings throughout America have become much more lethal, according to leading experts.

Given the scope of the emergency, immediate action is necessary. Here in California, Assemblymember Jesse Gabriel, D-Encino, has introduced legislation that addresses not merely machine gun conversion devices, but the firearm itself. His bill, Assembly Bill 1127, would prevent licensed firearm dealers in the state from selling semiautomatic pistols that can be easily converted into machineguns.

The City of Chicago, and, separately, a coalition of state attorneys general, have sued Glock, alleging the design of its weapons has enabled them to easily be transformed into machine guns.

Glock has allegedly has known for years about the flaw in its design, and firearm industry experts indicate it would be feasible for gun makers such as Glock to make it more difficult to attach the devices to their pistols. Thus far, however, Glock has failed to take sufficient action.

In the wake of carnage on streets littered with more than 100 shell casings from a mass shooting involving a machine gun conversion device-equipped handgun, Randall Woodfin, the mayor of Birmingham, Alabama, declared the devices “the number one public safety issue in our city and state.” He was far from alone. In recent years, law enforcement from Cincinnati to Sacramento have contended with mass shootings attributed to shooters who affixed these devices to their guns. The Bureau of Alcohol, Tobacco, Firearms and Explosives reported a 570% increase in the recovery of machine gun conversion devices from 2017-21 — and the problem has only continued to escalate since.

Like machine guns, machine gun conversion devices themselves are illegal under both federal and California law. But because these devices are so tiny, simple to produce using 3D printers and easy to obtain on the internet, they have become dangerously prevalent.

Law enforcement and other officials have been searching for solutions. Last fall, the U.S. Department of Justice established a federal anti-machine gun conversion device task force; the former U.S. Attorney for Massachusetts seized the domains of 350 sites that were selling such devices; scientists and industry officials have begun exploring ways to make 3D printing of these devices more difficult; and prosecutors throughout the nation have embarked on public education campaigns to alert the public to the dangers of the devices, with some offering sizable rewards to encourage reporting of the use and possession of machine gun conversion devices.

Gabriel’s bill has passed the State Assembly and is pending in the State Senate. Its enactment would be both intrinsically important and, potentially, the catalyst for comparable legislation in statehouses across the nation. Similar bills have been introduced in other states, but California must do what it does best: lead.

Mike Feuer is the former Los Angeles City Attorney and co-founder and former co-chair of Prosecutors Against Gun Violence, the nation’s first coalition of prosecutors to focus on preventing gun violence.

This story was originally published August 14, 2025 at 6:00 AM with the headline "California lawmakers must prevent the sale of DIY machine guns | Opinion."