The BFSIII binary trigger from Franklin Armory provides legal rapid-fire function.

Thanks to one hotel window, one psychotic man, and some very poor security, a mass shooting led to the ban of the legendary bump stock by our supposedly pro-Second Amendment President. The Las Vegas shooter who opened fire on a concert crowd in 2017 had rifles outfitted with the rapid-fire device that many of us came to know and love. Just one year later, an executive order straight from the White House put the brakes on sales and ownership thereof, and the feds demanded all bump stocks be destroyed or turned in. Womp.

But that’s okay. This guide discusses the legality and basis of the wording used for the bump stock ban. Most importantly, we’re going to look at how various firearm accessory makers and trigger manufacturers have innovated and brought to market some great rapid-fire alternatives to the bump stock. Here’s how to legally enjoy rapid-fire on your favorite black rifle without a bump stock.

How Did the Bumpstock Work?

Enjoy a quick blip from one of the former bump stock big names, Slide Fire:

The short-n’-sweet of the bump stock is simple: The rifle rests inside a fixed stock which also includes a fixed pistol grip. Like a normal buttstock, the buffer tube is captured inside the stock’s retainer. Yet in this case, the entire rifle can still slide back and forth. Think of it like a loose M4-type adjustable buttstock with a broken adjustment lever. The important part of the bump stock is the trigger well: The part of the stock that becomes the pistol grip also includes a molded grip for your trigger finger. Now, instead of squeezing the trigger with your finger, your finger remains static and rests in front of the trigger. Your off-hand holds the handguard and pulls the rifle forward, away from the stock. As you pull the rifle forward, the trigger hits your trigger finger. Boom, shot fired. The recoil drives the rifle back into the bump stock. The forward pressure applied by your off-hand pulls the rifle forward again, and the trigger hits your finger. Rinse, repeat. And as you can see, that repetition turns into a wickedly fun high rate of fire.

How, Exactly, Are Bump Stocks Banned?

It’s important to understand how the bumpstock ban was written. This will help us determine what devices and accessories are still legal to use based on their function. The executive order issued by the White House in 2018 instructed the Department of Justice to investigate the function of bump stocks and, as a result, the definition of the term “machinegun” changed. The ATF now describes bump stocks as such:

“Bump-stock-type devices are ‘‘machineguns’’ as defined by the NFA and GCA because such devices allow a shooter of a semiautomatic firearm to initiate a continuous firing cycle with a single pull of the trigger. Specifically, these devices convert an otherwise semiautomatic firearm into a machinegun by functioning as a self-acting or self-regulating mechanism that harnesses the recoil energy of the semiautomatic firearm in a manner that allows the trigger to reset and continue firing without additional physical manipulation of the trigger by the shooter. Hence, a semiautomatic firearm to which a bump-stock-type device is attached is able to produce automatic fire with a single pull of the trigger.”

So, how do we get around this language? What trigger enhancements are available that don’t land us in the black van of an ABC agency?

Option #1: The Binary Trigger

The BFSIII AR-C1 Binary Trigger from Franklin Armory provides legal rapid-fire for various weapons.
The BFSIII-C1 Binary Trigger from Franklin Armory.

Binary triggers like the BFSIII C1 Series of triggers from Franklin Armory perfectly overcome the federal bump stock ban’s language by allowing the shooter to fire a round on the first trigger squeeze and by firing a second round when the trigger is reset. Since the second round is only fired when the shooter manipulates the trigger by allowing it to reset, the binary trigger runs perfectly counter to the new definition of a machinegun.

The BFSIII triggers are manufactured for the CZ Scorpion, APC9, APC45, GHM9, GHM45, HK-91, HK-93, MP5, ACR, AR-15 and mil-spec AR platform (like the AR9 and 300 Blackout), and the AK platform.

How the Binary Trigger works:

When the trigger is pulled on a semiautomatic weapon, the sear releases the hammer. The hammer strikes the firing pin to ignite the round in the chamber. After firing, the bolt rides back and the hammer is pushed down to be reset. But because you just pulled the trigger, the sear’s not in place to capture the hammer. Instead, a disconnector captures the hammer with a small hook. As the trigger’s released, the disconnector releases the hammer so the sear captures it again.

The BFSIII Binary Trigger uses a second sear to provide rapid-fire function.
The components of the Binary Trigger include a second sear and different spring weights to dial in your rate of fire and ensure your weapon cycles reliably.

The binary trigger works by adding a second sear. Instead of the disconnector capturing the hammer after firing, the second sear does. Now your factory trigger is reversed: Keeping it squeezed stops the round from firing, and releasing the trigger releases the second sear so the hammer can strike the firing pin again. Once this second round is fired, the factory disconnector and sear take over again. Rinse and repeat.

How well does the Binary Trigger work?

Pretty damn well. With the right trigger squeeze and a solid grip, one can achieve simulated full-auto fire. The best part: You’re still (by legal definition) pulling the trigger with round fired. As of May, 2020, binary triggers like the Franklin Armory BFSIII are legal in most states.

Have any states outlawed binary triggers?

Yes. Binary triggers are currently banned in California, D.C., Iowa, North Dakota, New York, New Jersey, Maryland, Washington, Hawaii, Rhode Island, Florida, and Connecticut. In Delaware, BFSIII triggers can be sold only for pistol and non-rifled firearms.

Are there other binary triggers available?

Yes. Franklin Armory unveiled the 22-C1 Binary Trigger for the Ruger 10/22 platform. The .22 trigger is available for preorder and will be released at the end of June, 2020. Competing trigger maker Fostech introduced its own version of the binary trigger called the Echo
Sport Binary. It’s currently only available for the AR-15 and functions like the Franklin Armory unit. It’s a tad less expensive. The same state bans apply for the Fostech trigger.

Option #2: Crank Trigger

The Crank Trigger does exactly what the name implies:

It takes the original concept of the erstwhile Gatling Gun and applies that rotating crank trigger function to the modern semiautomatic rifle (or pistol). There are a few manufacturers producing crank trigger assemblies, though Gat Crank is the most popular option on the market. Not much more needs to be said about crank triggers. If you want to know more, check out our review of the Gat Crank.

Honorable Mention: Hell-Fire Trigger Mods

Hell-fire trigger mods consist of a collection of different parts and handheld “trainers.” These modifications either install in front of or behind the trigger, or they’re handheld and provide a means for positiong the shooting hand and trigger finger to achieve easy rapid-fire. These mods are often made by smaller gunsmiths and mom-n’-pop shops. When used correctly, a hell-fire trigger (depending on the design) can provide rapid-fire that could arguably beat the rate of fire achieved with a binary trigger. Most hell-fire trigger kits are finicky. They often use finely tuned springs or flexible “pedals” that need to be installed just right. But once used correctly, they provide an impressive rate of fire.

How the Typical Hell-Fire Trigger Works

Shown above is the original Hell-Fire Trigger, demonstrated with an updated configuration. It’s produced by a small outfit in Colorado and works with little “fine-tuning” and knowledge. This mod works in similar fashion to a bump stock, minus the stock and legal hurdles. Since you’re still operating the trigger with your hand and a stock is not being used to assist in rapid-fire by harnessing recoil energy, the Hell-Fire Trigger gets a clean pass with the ATF and other ABC agencies. It’s currently available at Firequest for the AR-15, AK-47, and “ranch” rifles such as the Mini-14 and Ruger 10/22.

Is the Hell-Fire Trigger legal?

Yes. No federal law currently exists which defines the Hell-Fire trigger as a machinegun. Hell-Fire Triggers are banned in certain states, including California, Connecticut, Delaware, Florida, Hawaii, Maryland, Massachusetts, Minnesota, New Jersey, Rhode Island, Vermont, and Washington.

There is an alternative to the original Hell-Fire. It’s called the Hell-Fire Stealth and doesn’t use any hand assist. Instead, the Stealth version replaces your AR-15’s pistol grip screw with an adjustable set screw. The adjustable screw enters the cavity of the lower receiver beneath the trigger and applies pressure to the disconnector, effectively reducing the travel distance of the trigger. The Hell-Fire Health is (at the time of publication) legal in all 50 states.

Is there any advantage to the Hell-Fire trigger over a Binary Trigger?

Certainly. The Hell-Fire trigger doesn’t replace your factory trigger, there is no complex installation required, and it can be removed in a few seconds if required. It is also much less expensive than a Binary Trigger.