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 poster advertises the highly anticipated video game, “Call Of Duty: Modern Warfare 3” at a GameStop Corp. store November 6, 2011 in North Las Vegas, Nevada. Video game publisher Activision plans to release the eighth installment in the “Call of Duty” franchise at midnight on November 8. (Photo by Ethan Miller/Getty Images)

General view of the stands in the Atrium during the Big Fashion Wardrobe Spring/Summer fashion and beauty event at Westfield London shopping centre on March 29, 2011 in London, United Kingdom.

In this photo taken on February 21, 2017, shooting instructor Kim Su- Ryon poses for a portrait at the Meari Shooting Range in Pyongyang Kim is holding a “Paektusan” target pistol, gifted by late North Korean leader Kim Il- Sung. Visitors to the range can pay 10 USD to shoot ten rounds. (Photo by Ed Jones/AFP Photo)

A model presents a creation by DB Berdan during the Mercedes-Benz Fashion Week in Istanbul, Turkey March 28, 2018. (Photo by Osman Orsal/Reuters)

A woman looks at traditional Ukrainian Easter eggs “Pysanka”, installed as part of the upcoming celebrations of Easter, in central Kiev, Ukraine, April 29, 2016. A pysanka is a Ukrainian Easter egg, decorated with traditional Ukrainian folk designs using a wax-resist (batik) method. The word pysanka comes from the verb pysaty, “to write”, as the designs are not painted on, but written with beeswax. Many other eastern European ethnic groups decorate eggs using wax resist for Easter. These include the Belarusians, Bulgarians, Croats, Czechs, Hungarians, Lithuanians, Poles, Romanians, Serbs, Slovaks, Slovenes and Sorbs. (Photo by Valentyn Ogirenko/Reuters)

A man sells traditional doll toys and sweets for children to celebrate the birthday of prophet Muhammad, also known as “mawlid al nabi”, which will fall next week, in a makeshift tent in Cairo, December 30, 2014. (Photo by Mohamed Abd El Ghany/Reuters)

Two male African mantis Pseudempusa pinnapavonis (Peacock Mantis) show their colours in Igor's home studio in Munich, Germany. (Photo by Igor Siwanowicz/Barcroft Media)