This is an important message from the Bureau of Alcohol, Tobacco, Firearms and Explosives. All FFLs should be aware that Machinegun Conversion Devices (MCDs) is a part, or a combination of parts, designed to modify a semi-automatic firearm so it is capable of firing automatically more than one shot by a single function of the trigger. These devices, often called switches, chips, auto sears are considered machineguns under the law. The possession, manufacture, and/or sale of machinegun conversion devices without proper licensing is a federal offense.

Please see the attach flyer which illustrates different Machinegun Conversion Devices (MCDs). These devices are defined as machineguns under the National Firearms Act, even when not installed. We encourage FFLs who encounter these devices to immediately contact your local law enforcement office or nearest ATF office.