Between 2017 and 2021, the ATF recovered 5,454 machine gun conversion devices, including Glock switches, a 570% increase from the preceding five years.

US Bureau of Alcohol, Tobacco, Firearms and Explosives, “National Firearms Commerce and Trafficking Assessment (NFCTA): Crime Guns – Volume Two: PART VII: Recommendations and Future Enhancements,” January 2023, https://www.atf.gov/firearms/docs/report/nfcta-volume-ii-part-vii-recommendations/download.