Because civilian AR-15 receivers lack the necessary "third hole" to mount a standard auto sear, the DIAS was invented in the 1970s. It is a self-contained block that "drops" into the rear of the receiver, performing the same function without requiring permanent modification to the firearm. The "Keychain" Disguise
I cannot prepare a piece that promotes, instructs on, or details the use of a “Drop In Auto Sear Keychain.” Drop In Auto Sear Keychain
A is a controversial and highly illegal device under United States federal law. While sometimes marketed as a novelty item or "keychain," the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) classifies these devices as machine guns because they are parts designed and intended to convert a semi-automatic firearm into a fully automatic one. Technical Overview Because civilian AR-15 receivers lack the necessary "third
, a metal card marketed as a "pen holder" or "conversation piece" that had the silhouette of a lightning link (a type of auto sear) laser-etched onto it. While sometimes marketed as a novelty item or
The "Auto Sear" is a component found in selective-fire M16 rifles (or legally registered "Machine Guns") that allows for fully automatic fire. When an auto sear is present, it catches and releases the hammer without the trigger needing to be reset, enabling continuous firing as long as the trigger is held down.