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)

Penelope Cruz attends the Palme d'Or Award Ceremony held at the Palais des Festivals during the 63rd Annual Cannes Film Festival on May 23, 2010 in Cannes, France. (Photo by Sean Gallup/Getty Images)

A .44 Colt Dragon with a traditional Cowboy's hat. This weapon was originally used in the Mexican War of 1846-8 and it is typical of the type used in the “Wild West” of America. (Photo by Orlando /Three Lions/Getty Images). Circa 1950

In this Friday, February 1, 2019, photo, Filipino-Chinese display piggy banks at the start of celebrations leading to next week's Lunar New Year in Chinatown, Manila, Philippines. This year is the Year of the Earth Pig on the Lunar calendar and is supposed to represent abundance, diligence and generosity. (Photo by Bullit Marquez/AP Photo)

This photo provided by NASA astronaut Christina Koch shows the launch of a Russian Soyuz rocket, as seen from the International Space Station on Wednesday, September 25, 2019. (Photo by Christina Koch/NASA via AP Photo)

Tightrope walker Tatian-Mosio Bongonga hangs from a tightrope as she pauses while scaling the Monmartre hill towards the Sacre Coeur Basilica (not pictured) in Paris, France, July 20, 2018. (Photo by Philippe Wojazer/Reuters)

English fashion designer Mary Quant (R) with a group of models at Heathrow Airport, before leaving for a continental fashion tour, 18th March 1968. (Photo by Express/Getty Images)

New York Rangers right wing Ryan Reaves punches Minnesota Wild left wing Marcus Foligno (17) during a third-period fight in an NHL hockey game Thursday, October 13, 2022, in St. Paul, Minn. (Photo by Aaroan Lavinsky/Star Tribune via AP Photo)