Summary: AR15 Drop In Auto Sears (DIAS) manufactured after October 31st, 1981 are considered machine guns and are therefore regulated under the National Firearms Act of 1934.
IMPORTANT: Despite this ruling, possession of ANY Drop In Auto Sear along with an AR-15 with some M16 parts constitutes a machinegun.
The Firearm Owners Protection Act of 1986 modified the definition of machineguns to include parts designed for automatic fire. This change made DIAS, as parts, machineguns.
Despite a few court rulings to the contrary, it seems that “pre-81” DIAS are still treated as exempt. Multiple courts have said that the ATF has no authority to arbitrarily “grandfather” pre-81 auto sears.
Proceed with extreme caution when dealing with DIAS. Or, get your FFL and get as many machine guns as you want. 😉
Background: This ruling is in response to devices called Drop In Auto Sears which can convert certain AR-15 style rifles into machine guns along with certain other parts.
Machinegun: 26 U.S.C. 5845(b) – The term “machinegun” means any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun, and any combination of parts from which a machinegun can be assembled if such parts are in the possession or under the control of a person.
What the ATF Said: Because DIAS can be used to cause an AR-15 to function as a machinegun, then the DIAS itself is a machinegun. However, the ATF also said that DIAS made before a certain date are “grandfathered.” Numerous courts have disagreed with the ATF and ruled that they do not have the authority to arbitrarily “grandfather” certain items from the law.
Pre-1986 machine guns are perfectly legal to own under federal law. If you’d like to get them MUCH cheaper and also get brand new machine guns, you’ll need an FFL. It’s very easy to get one!
ATF Ruling 81-4:
27 CFR 179.11: MEANING OF TERMS
The AR15 auto sear is a machinegun as defined by 26 U.S.C. 5845(b).
ATF Rul. 81-4
[Status of ruling: Active]
The Bureau of Alcohol, Tobacco and Firearms has examined an auto sear known by various trade names including “AR15 Auto Sear,” “Drop In Auto Sear,” and “Auto Sear II,” which consists of a sear mounting body, sear, return spring, and pivot pin. The Bureau finds that the single addition of this auto sear to certain AR15 type semiautomatic rifles, manufactured with M16 internal components already installed, will convert such rifles into machineguns.
The National Firearms Act, 26 U.S.C. 5845(b), defines “machinegun” to include any combination of parts designed and intended for use in converting a weapon to shoot automatically more than one shot, without manual reloading, by a single function of the trigger.
HELD: The auto sear known by various trade names including “AR15 Auto Sear,” “Drop In Auto Sear,” and “Auto Sear II,” is a combination of parts designed and intended for use in converting a weapon to shoot automatically more than one shot, without manual reloading, by a single function of the trigger. Consequently, the auto sear is a machinegun as defined by 26 U.S.C. 5845(b).
With respect to the machinegun classification of the auto sear under the National Firearms Act, pursuant to 26 U.S.C. 7805(b), this ruling will not be applied to auto sears manufactured before November 1, 1981. Accordingly, auto sears manufactured on or after November 1, 1981, will be subject to all the provisions of the National Firearms Act and 27 C.F.R. Part 179.