An unknown number of guns are being built with the mechanisms, causing problems for the police and ATF officials. Photo: An ATF agent holds a generic unfinished receiver, back, and one that has been manufactured, front, at an ATF field office in Washington, on May 06, 2014. The ATF is trying to crack down on the trade in the makeshift guns by targeting shops and individuals who offer to turn the unfinished receivers into functional pieces for firearms. (Photo by Bill O'Leary/The Washington Post)

Lady officers of the Philippine National Police force show the taped muzzle of their guns at a police camp in Taguig City, south of Manila, Philippines, 22 December 2014. Law enforcement units all over the country held a ceremonial taping of firearms as a counter measure against cases of indiscriminate firing and illegal discharge of service weapons during the upcoming Christmas and New Year celebrations. (Photo by Francis R. Malasig/EPA)

The Patrouille Suisse jets perform prior to the Men's Downhill race at the Fis Alpine Skiing World Cup in Wengen, Switzerland, 15 January 2022. (Photo by Jean-Christophe Bott/EPA/EFE)

Italy's Federica Brignone's helmet is seen after their run at the FIS Alpine Ski World Cup in Garmisch-Partenkirchen, Germany, on January 25, 2025. (Photo by Gintare Karpaviciute/Reuters)

Travis Gerrits of Canada competes during qualifying for the Mens Aerials at the FIS Freestyle Ski World Cup Aerial Competition at Deer Valley on January 10, 2014 in Park City, Utah. (Photo by Mike Ehrmann/Getty Images)

Norway’s Daniel Andre Tande falls to the ground during the FIS Ski Jumping World Cup Flying Hill Individual competition in Planica on March 25, 2021. (Photo by Jure Makovec/AFP Photo)

Lindsey Vonn of USA wins the bronze medal during the FIS World Ski Championships Women's Downhill on February 10, 2019 in Are Sweden. (Photo by Leonhard Foeger/Reuters)

France's Romane Miradoli competes during the Women's Downhill event of the FIS Alpine Ski World Championship 2023 in Meribel, French Alps, on February 11, 2023. (Photo by Lionel Bonaventure/AFP Photo)