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)

A person shelters from the rain in a flooded underpass by Lawrence Hill Roundabout, Bristol on Monday, September 23, 2024. An amber weather warning for heavy rain has come into force in parts of England, with the Met Office warning that affected areas could experience more than a month's worth of rain falling on Monday. (Photo by Ben Birchall/PA Images via Getty Images)

The main entrance and blast door at the nuclear bunker site on the Woodside Road industrial estate on February 4, 2016 in Ballymena, Northern Ireland. The underground shelter has been put up for sale by the offices of the Northern Ireland First and Deputy First Minister. The bunker which was completed in 1990 was built to hold up to 235 people in the event of a nuclear bomb and is complete with kitchen facilities, dormitories and decontamination chambers. The site, one of approximately 1,600 nuclear monitoring posts built in the UK since 1955, is on the housing market with an asking price of £575,000. (Photo by Charles McQuillan/Getty Images)

Iraqi security forces vehicles take part in a military parade in the streets of Baghdad, Iraq July 12, 2016. Social media activists posted images of tanks, armored vehicles, cannons, soldiers, police officers, and PMF members in Saadoun Street. The photos spiked a rumor of military coup. Military and security advisor and expert Lt. Diyaa al-Wakil said that it is only normal for such rumors to spread since there were no prior announcements about the training. (Photo by Khalid al Mousily/Reuters)

Middlesbrough star Paul Gasgoigne is confronted by streakers at The Riverside on December 6, 1998 during their match against Newcastle. (Photo by Owen Humphreys – PA Images/PA Images via Getty Images)

Hugo Gonzalez of Lake Worth works to put final strokes on his rendition of a Raksha demon. (Photo by Thomas Cordy/The Palm Beach Post)

British television presenters Trinny Woodall (centre right) and Susannah Constantine (centre) lead almost 900 women in throwing their old bras into the air in Rothwell town square in Rothwell, Northamptonshire on May 7, 2007. (Photo by Clara Molden – PA Images/PA Images via Getty Images)

A Tibetan woman with horses in a remote area of the Yushu Autonomous Prefecture of the Tibetan Plateau on May 31, 2016. (Photo by Giulia Marchi/The Washington Post)