A is a small mechanical component designed to convert a semi-automatic AR-15 into a fully automatic firearm. While often marketed as a "keychain" or "paperweight" to bypass legal scrutiny, federal law in the United States classifies these devices as machine guns in their own right.
In a standard semi-automatic AR-15, the trigger must be pulled for every shot fired. A true military M16 uses an internal part called an to hold the hammer back until the bolt is fully closed, allowing for continuous fire. Drop In Auto Sear Keychain
: Sellers use these labels to evade customs and detection by law enforcement. A is a small mechanical component designed to
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 A true military M16 uses an internal part
The following article explores the history, mechanical function, and severe legal risks associated with these devices. What is a Drop-In Auto Sear (DIAS)?