Are Binary Triggers Legal in Michigan?

Short answer: Yes, binary triggers are currently legal to possess, install, and use in Michigan. Neither state law nor federal law explicitly bans them.

Are Binary Triggers Legal in Michigan?

Yes, binary triggers are currently legal to possess, install, and use in Michigan. Neither state law nor federal law explicitly bans them. They are not classified as machine guns because they fire only one round per single function of the trigger—once on pull and once on release.

Defining the Legal Landscape in Michigan

The question of binary trigger legality in Michigan hinges on a single, critical concept: the legal definition of a machine gun. Michigan firearm laws, specifically MCL 750.224, define a machine gun as a firearm that shoots or is designed to shoot automatically more than one shot, without manual reloading, by a single function of the trigger. This language closely mirrors the federal definition used in the National Firearms Act (NFA).

Binary triggers operate in a unique way that, according to the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), does not meet this definition. A binary trigger fires one round when you pull the trigger and a second, separate round when you release the trigger. The ATF has repeatedly affirmed that since the pull and the release are two distinct functions, a firearm equipped with a binary trigger is not a machine gun. Because Michigan's state law lacks a specific prohibition on such devices and generally defers to the federal interpretation on matters of firearm function, binary triggers occupy a legal space in the state.

However, this legality is not absolute and depends entirely on the proper functioning of the device. If a binary trigger were to malfunction and fire multiple rounds on the pull or release—a phenomenon known as 'hammer follow'—it could be considered an illegal, unregistered machine gun. This places a significant burden on the owner to ensure their equipment is installed correctly and maintained in good working order. Responsible gun ownership is paramount, and understanding the nuances of both state and federal law is the first step for anyone considering this type of modification. For a general overview of legal firearm acquisition, our guide on how to buy a gun provides essential information.

How Binary Triggers Function Mechanically

To appreciate the legal argument, it's essential to understand the mechanics. A standard semi-automatic trigger resets the hammer only after the trigger is released and pulled again for the next shot. A binary trigger adds a second sear surface that catches and releases the hammer upon the release of the trigger.

Here's a simplified breakdown of the firing sequence:

1. Selector Switch: The user selects one of three modes: Safe, Semi-Automatic, or Binary.

2. Trigger Pull: In binary mode, pulling the trigger rearward fires the first round, just like a standard trigger.

3. Trigger Release: As the bolt cycles and chambers a new round, holding the trigger back keeps the hammer from falling. Releasing the trigger forward allows the secondary sear to release the hammer, firing a second round.

This pull-and-release action is the cornerstone of its legality. Unlike a bump stock, which uses recoil to create a continuous firing cycle from a single trigger pull, or a forced reset trigger, which has faced its own legal challenges, the binary trigger requires two separate actions from the shooter's finger for two shots. This is a critical distinction that keeps it outside the legal definition of 'machine gun'. The ATF has issued several private determination letters confirming this interpretation for specific models from manufacturers like Franklin Armory and Fostech.

Navigating State vs. Federal Interpretations

While Michigan law is the ultimate authority within the state, federal precedent from the ATF carries immense weight, especially when state statutes are not explicit. Michigan's definition of a machine gun in MCL 750.224(1)(a) is functionally identical to the federal one. This alignment means that Michigan law enforcement and courts are highly likely to follow the ATF's technical guidance on what constitutes a single 'function of the trigger.'

This situation is different from that of other trigger mechanisms. For example, the legal status of forced reset triggers has been far more contentious, with the ATF classifying them as machine guns. You can see how this plays out in other states by reading about forced reset triggers in Florida, where the legal battle has been prominent. The key takeaway for Michigan residents is that as long as the ATF considers binary triggers to be semi-automatic modifications, they are unlikely to face challenges under current state law.

It's also worth noting that this could change. State legislatures can, and do, pass laws that are more restrictive than federal ones. A future bill could specifically target binary triggers or redefine 'function of the trigger' at the state level. Gun owners should always stay informed about pending legislation in Lansing to avoid inadvertently violating a new regulation.

Practical Considerations and Potential Risks

Owning a binary trigger comes with responsibilities beyond just legal compliance. Proper installation is critical. Many manufacturers recommend or require the use of anti-walk pins to prevent the trigger and hammer pins from moving under the increased stress of rapid firing. Improper installation can lead to malfunctions that might not only be dangerous but could also cause the firearm to fire in a way that legally reclassifies it as a machine gun.

Another consideration is ammunition and buffer weight. The increased rate of fire can be demanding on a firearm's gas system. Tuning your rifle's buffer system (the buffer and spring) is often necessary to ensure reliable cycling and prevent out-of-battery detonations or excessive wear on components. Using quality ammunition is also advised, as cheap, underpowered rounds may not have enough force to cycle the action reliably at high speed.

Many popular modern platforms are well-suited for these upgrades. For instance, the SIG Sauer MPX is a common host for binary triggers due to its robust design. Regardless of the platform, the owner must be proficient with the firearm's function in binary mode. The speed can be surprising, and mastering trigger control is essential for safety and accuracy. It's not a simple drop-in upgrade for a novice shooter.

Comparison to Other Rapid-Fire Devices

Binary triggers exist in a category of accessories designed to increase a firearm's rate of fire. It's helpful to compare them to other devices to understand their unique legal and mechanical status.

Bump Stocks: These devices were banned by federal rule in 2018. A bump stock replaces the rifle's standard stock and allows the firearm to slide back and forth, using the recoil to 'bump' the shooter's stationary trigger finger, resulting in continuous fire. The ATF reinterpreted the 'single function of the trigger' to include the single, continuous pull required to activate a bump stock.

Forced Reset Triggers (FRTs): These triggers use the energy from the bolt carrier to forcibly reset the trigger, allowing for a very rapid rate of fire. The ATF has classified FRTs as machine guns because they believe the trigger is not being reset by the shooter's finger but by an internal mechanism, thus firing more than one shot per 'function.' The legality of forced reset triggers in Texas and other states remains a subject of intense legal debate.

Binary triggers remain distinct because the shooter's finger must perform two distinct movements (pull and release) for two shots. This fundamental difference is why they have, thus far, avoided the legal fate of bump stocks and FRTs. Anyone looking to acquire a firearm suitable for such a modification can browse all gun listings to see available platforms.