A Glock switch is one type of a machine gun conversion device. It’s a metal or plastic piece, about the size of a coin, that attaches to the back of Glock pistol, a brand that is popular with ...

(AP Photo/Alex Brandon, File) A semi-automatic Glock pistol is fired at the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), National Services Center, March 2, 2023, in Martinsburg, W.Va.