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)

People take photos in a field of Yellow Desert Sunflowers as wildflowers begin to bloom in Anza-Borrego Desert State Park in California after a record-setting wet winter of rain, Anza-Borrego Desert State Park, California, U.S. March 20, 2024. (Photo by David Swanson/Reuters)

Grace Sun, from Shenzhen China, poses for a picture outside Capital One Arena, ahead of a rally for U.S. President-elect Donald Trump the day before he is scheduled to be inaugurated for a second term, in Washington, U.S., January 19, 2025. “I think it's a very good thing between China and America”, said Sun. “I think cooperation will be better”. (Photo by Marko Djurica/Reuters)

People travel in a taxi carrying sheep on a luggage carrier and in the car boot in Kandahar October 30, 2021. (Photo by Bulent Kilic/AFP Photo)

A Land Rover Discovery has been crashed and abandoned inside a canal lock in Tipton, United Kingdom on Monday morning, November 14, 2022. There were no reported injuries and the car is expected to be removed on Tuesday. (Photo by Katie Stewart/Alamy Live News)

People take part in mass water fights during the first day of Songkran, or Thai New Year, on Khao San Road in Bangkok on April 13, 2023. (Photo by Lillian Suwanrumpha/AFP Phoot)

Tourists visit an art installation of colorful umbrellas on November 10, 2022 in Nanjing, Jiangsu Province of China. (Photo by VCG/VCG via Getty Images)

Dublin Horse Show mascot “Conor the Capall” among the crowds on the opening day of the 147th Dublin Horse Show at the RDS on Wednesday, August 17, 2022, the first to be held since 2019. The event which was first held in 1864 takes place over the next five days and includes national and international show jumping competitions. (Photo by Brian Lawless/PA Images via Getty Images)