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)

Biologist Kelly Martin records her measurements of Electra, a 5 1/2 foot leatherback turtle nesting on the beach behind the Seminole Golf Club course in Juno Beach. Martin uses a red light which is invisible to turtles. (Photo by Greg Lovett/The Palm Beach Post)

A humpead wrasse, transported from Japan's southern island of Okinawa, swims with other tropical saltwater fish on display in a tank for the Sony Aquarium 2017 exhibition in Tokyo on July 31, 2017. The Sony Aquarium 2017 exhibition, featuring marine life common to the waters around Okinawa, runs until August 13. (Photo by Kazuhiro Nogi/AFP Photo)

English television personality from Newcastle, known for being a cast member in the MTV reality series “Geordie Shore”, Chloe Ferry, 25, soaked up the sun in a thong latex bikini during her holiday in Portugal on May 28, 2021. (Photo by Backgrid USA)

English singer Rita Ora looked like she was sitting on a gold mine as she reclined in towering, metallic shoes and an open gown during a photoshoot in Los Angeles on August 5, 2021. (Photo by Instagram)

Afghan resistance movement and anti-Taliban uprising forces take part in a military training in Panjshir province on August 30, 2021. (Photo by Ahmad Sahel Arman/AFP Photo)

N.C. Dezendorf, wife of the general manager of the Electro-Motive division of General Motors, christens the new lightweight “Aerotrain” at the company's locomotive works in La Grange, Ill. on August 22, 1955. (Photo by Edward Kitch/AP Photo)

Yippie leader Jerry Rubin, barred on December 4, from House Un-American Activities subcommittee hearing, aims a toy gun in “self defense” outside the Washington hearing room on December 5, 1969. Rubin showed up in his Santa Clause suit because he believed it was typical of the committee which, he said, “is a total circus”. (Photo by Bob Daugherty/AP Photo)