What’s the difference between a binary trigger and a forced reset trigger? Both are “drop in” mechanisms for standard AR-15 rifles and pistols. Both produce a near full-auto experience. Each one is legal. Both types are relatively available, though either one is very hard to get at what one might call a reasonable price without fighting a frenzy of super-ready clickers waiting by their device to snag a handful the very second they go on sale via ecommerce. But that’s where the similarities end. Below is a brief description of how each one works. From these explanations, the difference between binary and forced reset triggers is clear.

UPDATE 24MAR2022: In an open letter to all FFL Dealers, the ATF has officially declared that FRTs are machine guns. The statement is as follows:

ATF’s examination found that some FRT devices allow a firearm to automatically expel more than one shot with a single, continuous pull of the trigger. For this reason, ATF has concluded that FRTs that function in this way are a combination of parts designed and intended for use in converting a weapon into a machinegun, and hence, ATF has classified these devices as a “machinegun” as defined by the NFA and GCA.

“Machinegun” is defined under 26 U.S.C. § 5845(b) and 18 U.S.C. § 921(a)(23) as—

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.

Under 26 U.S.C. § 5871, any person who violates or fails to comply with the provisions of the NFA may be fined up to $10,000 per violation and is subject to imprisonment for a term of up to ten years. Further, pursuant to 26 U.S.C. § 5872, any machinegun possessed or transferred in violation of the NFA is subject to seizure and forfeiture. Under 18 U.S.C. § 924(a)(2), any person who violates § 922(o) may be sent to prison for up to 10 years and fined up to $250,000 per person or $500,000 per organization.

BOTTOM LINE: The ATF has declared that FRTs are now subject to the GCA and NFA, and thus require the same tax, stamp, and paperwork as other NFA items such as SBRs or suppressors. Here’s the Reddit discussion on the same matter.

How do binary triggers work?

A binary trigger works by using the reset action to fire another round. What’s that mean? When a regular trigger in a semiautomatic rifle resets, meaning returns to its original position after you fire one round, the mechanism resets and is ready for the user to pull the trigger again to fire another round.

A binary trigger uses the reset spring action to actually strike another cartridge. Your finger pulls the trigger, and the rifle fires a round. Then when your finger lets off the trigger, the rifle fires another round. Pull – Fire – Release – Fire – Pull – Fire – Release – Fire.

How do forced reset triggers work?

A forced reset trigger does exactly what its name implies. It forces the trigger to reset itself. It literally moves your finger forward as it resets. Therefore, if you maintain a constant pressure on the trigger, it will reset and then your pressure will pull it again. Pull-Fire-Pull-Fire-Pull-Fire.

Forced resets have built in “settings” (if it’s right to call them that) for single shot and for bypassing the rapid fire process. If you pull harder on the trigger than is necessary to fire a shot, it will fire one round, and then cease. Also, if you pull very lightly and release, you’ll only fire one round.

Are there any safety issues?

I asked our Gunsmith, Josh Mallet, about these triggers, their differences, and his preference. Josh was clear: “Binary triggers are not safe. I won’t install ’em.” Josh says there are too many moving and unstable parts in a binary trigger, and he’s seen far too many of them malfunction, regardless of maker or brand.