A switch on a gun, specifically known as a "Glock switch," is a small device that can be attached to the rear of the slide of a Glock handgun. It converts the semi-automatic pistol into a selective fire machine pistol capable of fully automatic fire. This means it allows the gun to fire continuously as long as the trigger is held down, rather than firing one round per trigger pull as in a standard semi-automatic pistol
. The Glock switch works by applying force to the trigger bar inside the gun, preventing it from limiting the firing to a single round per trigger pull. Normally, the trigger bar catches the firing pin after each shot until the trigger is released, but the switch holds it down to allow rapid firing. The device is roughly the size of a U.S. quarter and replaces the slide cover plate on the Glock pistol, adding a selective fire switch to toggle between semi-automatic and fully automatic modes
. These devices are not manufactured by Glock but are third-party aftermarket parts. They are classified as machine guns under U.S. federal law, making their possession illegal for civilians. The 1986 Firearm Owners Protection Act bans new machine guns for civilian ownership, and possession of an unregistered machine gun can result in severe penalties including fines and prison time
. Law enforcement agencies have reported a rise in the use of Glock switches in crimes, and they are often manufactured cheaply or 3D printed, making them increasingly accessible to criminals. The device has been linked to several mass shootings and violent crimes in the U.S.
. In summary, a "switch" on a gun like the Glock switch is a small, illegal device that converts a semi-automatic handgun into a fully automatic weapon by modifying its internal trigger mechanism
