A tiny, inexpensive device is all it takes to modify some semi-automatic handguns into illegal automatic weapons capable of firing multiple rounds with one pull of the trigger. These auto sear switches often turn up at homicide crime scenes across the country and have become a rapidly growing problem for law enforcement in recent years.
Maryland this week became the latest state to pass a law to address the surge of auto sears or Glock switches, as they're commonly known, because Glock 9 mm pistols are the kind of handgun most commonly modified this way. Meanwhile, New York recently introduced legislation that would go even further by outlawing the sale of any firearm that could be easily modified by an auto sear.
The federal Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) says the proliferation of auto sears has hit epidemic proportions. Nearly 5,500 devices were recovered by police departments from 2017 to 2021, according to the ATF. Director Steve Dettelbach warned last year that they are "flooding our communities."
Glock switches cost as little as $50
Also known as a trigger switch or a conversion device, these third-party add-ons can bypass a semi-automatic trigger mechanism, allowing the weapon to fire rounds in quick succession with a single pull. They can be purchased for as little as $50 or inexpensively made with a 3D printer.
"This increasing demand for machine guns by criminal elements does not just present a public safety danger, it is unsafe for law enforcement as well, who are increasingly outgunned by the weaponry they face," says Kristina Mastropasqua, an ATF spokesperson.
In 2022, a gunman armed with a Glock pistol modified with an auto sear opened fire in Sacramento, killing six people and wounding 12 others. Earlier this month, Shelby County District Attorney Steve Mulroy in Memphis, Tenn., lamented "a proliferation of machine guns ... [that] makes every police-citizen encounter even more fraught than it used to be." Concern has also been noted in Richmond, Va., and in Washington, D.C., where U.S. Attorney Matthew Graves called Glock switches "an incredibly serious problem."
Nick Suplina, senior vice president for law and policy at Everytown for Gun Safety, which describes itself as the largest gun violence prevention organization in the country, says that while these devices can be made to work on any "striker fired" pistol — weapons with such names as Sig Sauer, Ruger or Smith & Wesson — it is primarily "a Glock problem."
"Glock has known about this problem for decades and has opted not to change its design," Suplina says.
NPR reached out repeatedly to Glock's Smyrna, Ga.-based U.S. subsidiary for this story, but did not receive a response.
Legislatively, it has been a mixed bag
Federal regulations already prohibit conversion devices that can bypass a semi-automatic trigger mechanism. While Maryland is the latest state to take legislative action against these devices, similar efforts elsewhere have had mixed results. Republican governors in Virginia and Mississippi have signed legislative restrictions, while in Maine, where the legislature approved criminalizing auto sears, the bill was vetoed by Democratic Gov. Janet Mills. In Alabama, a bill to ban auto sears passed the House, but the 2024 session ended without a Senate vote. But none of those measures goes as far as New York's proposed law.
"There has been a big increase in these devices not only in New York, but across the country," says New York Sen. Zellnor Myrie, who is sponsoring the legislation. This month marks two years since a mass shooting in Buffalo that killed 10 people and Myrie, who is running for New York City mayor, says "we want to do everything we can to make our state safer."
New York's move to ban the sale of any handgun that can be modified is "a huge thing," says Daniel Webster, a professor at Johns Hopkins University's Center for Gun Violence Solutions. Because auto sears are so easy and inexpensive to get, "adaptations to the firearm itself would be the way to go," he says.
Mark Oliva, the managing director of public affairs for NSSF, the firearm industry trade association, says New York's proposed legislation appears to be directed at Glock. But it "would essentially ban not just Glocks, but nearly all striker-fired handguns and potentially could ban any firearm," because of its vague language, he says.
In Chicago, where more than 1,000 modified pistols have been recovered in the past two years, city officials are suing Glock to force the company to change its design so that auto sears would be more difficult to install.
Would a redesigned Glock be less reliable?
However, Oliva notes that many police departments — including New York City's — use Glocks because of their reputation for reliability. He says if Glock is forced to retool its semi-automatic pistols, that reliability could be compromised.
Mark Pennak, president of the pro-gun group Maryland Shall Issue, agrees. "Glocks are extremely reliable and they're used a lot by law enforcement all over the country, including in the state of Maryland," he says. "So, I can understand the reluctance to be shamed into modifying what has proved to be a very successful and reliable design."
Pennak says existing federal laws, some that date back to the 1930s, already make it extremely difficult for a civilian to legally own a machine gun and thus make new state regulations unnecessary. As for Maryland, he says the new law is "a political stunt" that simply amends previous law to "add a particular definition that covers the Glock switch."
Baltimore County Executive John "Johnny O" Olszewski Jr. contends that the change is important because it closes a gaping loophole. "We've known this is a real problem," says Olszewski, who is running for Maryland's 2nd congressional seat in November. "But our police department in Baltimore County was unable to confiscate [auto sears] in the state because the law in Maryland did not reflect national law."
New York's proposal goes much further and, were it to become law, would likely face a challenge in federal court, proponents and critics alike agree.
"I would expect that this would be very problematic," Oliva says. "If it were to be signed into law, we would certainly take an assessment at that point of where we stand."
Webster, from Johns Hopkins, is more direct. "Obviously, the manufacturers have a lot at stake," he says. "And now they'll try to make a variety of legal challenges."
