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)

An attendee dances at the start of the “Big Goth Dance Party” during the Porcupine Freedom Festival, or PorcFest, the Free State Project's annual summer gathering in Lancaster, NH on Wednesday, June 25, 2014. (Photo by Matthew Cavanaugh/The Washington Post)

Vegetarian 19-year-old model Courtney Stodden gets ready to serve veggie hot dogs wearing a lettuce bikini during a People for the Ethical Treatment of Animals (PETA) free veggie dog handout on Capitol Hill in Washington, DC, July 16, 2014. (Photo by Jim Watson/AFP Photo)

A Free Syrian Army (FSA) fighter reacts as he mourns near the body of his brother, who was an FSA fighter and died during an offensive against Islamic State fighters to take control of Qabasin town, on the outskirts of the northern Syrian town of al-Bab, Syria January 10, 2017. (Photo by Khalil Ashawi/Reuters)

South Korea's Hur Yoonseo and Lee Riyoung take part in the Free Routine segment of the Artistic Swimming Women's Duet competition at the 19th Asian Games in Hangzhou, China, Saturday, October 7, 2023. (Photo by Ng Han Guan/AP Photo)

LCR Honda IDEMITSU's Japanese rider Takaaki Nakagami crashes in the second MotoGP free practice session of the Portuguese Grand Prix at the Algarve International Circuit in Portimao, on April 16, 2021. (Photo by Patricia de Melo Moreira/AFP Photo)

Artem, a 40-year-old Ukrainian commander, shouts a warning before his artillery team fires toward Russian positions near Pokrovsk in early October 2024. (Photo by Serhiy Nuzhnenko/Radio Free Europe/Radio Liberty)

France's Juliette Ducordeau (Front R) and fellow athletes react after crossing the finish line of the Women's Mass Start 10 km Free event at the FIS Tour de Ski stage on January 8, 2023 in Val di Fiemme. (Photo by Marco Bertorello/AFP Photo)