6 Best AR-15 Binary Triggers in 2024 [Buying Guide]

Binary triggers are awesome. They mount in a semi auto and give you the option to shoot in semi-auto or binary modes. A good one ensures basic functionalities, will be fairly easy to install, and you can find one at less than half the price and a lot less than half the trouble of an actual fully automatic gun.

Real quick before anyone jumps down my throat: best binary triggers operate completely differently from a fully automatic. They are two completely different things.

However, the entire point behind a binary triggers system is to shoot much faster than a semi-automatic can on its own, so talking about binary triggers and an automatic weapon in the same breath makes sense.

Whether you're just taking it to the shooting range or prepping, a binary trigger is worth considering.

Wait, Aren't Binary Triggers Illegal?

There are no federal laws against any of the best binary triggers as of the writing of this article. The last attempt by the federal government to ban a device that makes a semi automatic function more similarly to a fully automatic was the ban on bump stocks, and a federal court has issued an injunction preventing that ban from being enacted due to constitutional and legal issues with it.

However, there are a number of states who have banned any type of device that increases the maximum theoretical rate of fire from a semi-automatic weapon. As of the writing of this article in August 2021, these are the states where binary triggers are illegal:

• California

• Connecticut

• Florida

• Hawaii

• Iowa

• Maryland

• New Jersey

• New York

• Rhode Island

• Washington

• District of Columbia

Also, in Delaware they can only be used in pistol platforms...for some reason... If you live in one of those states, you won't be able to get one.

There is another concern that if and when the federal government finds a way to ban them, or the state that you live in decides to ban them, existing binary triggers may or may not be grandfathered in, which means you could end up dropping a fair amount of cash on something that you may have to end up giving up anyway.

Binary Trigger vs. Bump Fire Stocks vs. Fully Automatic

This is a good thing to clear up before we dive into these, because a lot of people have heard a little bit about some of the best binary triggers but don't really understand them, and it's important to understand exactly what's happening here. Let's start in reverse order.

Fully Automatic Firearms

A full auto firearm is one that continuously feeds new rounds into the chamber as long as the trigger is held down which causes a smooth trigger pull and there are rounds to be fed.

The fire rate gets so high that you become limited by the barrel getting too hot and the time it takes to reload more than anything else.

An M4, for example, can fail after 400 rounds of ammo in full auto, which, depending on how you're feeding it, could be done in less than a minute. Because on a fully automatic you're just holding down the trigger, it's easier to maintain a certain degree of accuracy while sustaining full auto fire.

"Bump" Modifications

It's worth noting that a special stock is not required to bump fire; anything that allows you to use the recoil from a shot to bounce the gun back forward into your finger will give you the ability to bump fire.

The action of the firearm isn't changed at all, it's just the recoil above and beyond what is used to cycle the bolt is then used to physically move the gun backwards and forwards.

That said, a bump stock works by doing exactly that - you pull the trigger once, and the recoil moves the rifle back and then forward and as long as you hold your finger in the same place the trigger will reset when it goes back and then pull again when the rifle comes forward. The function of the rifle is still firmly semi-automatic, you've just found a way to shoot faster.

Maintaining any semblance of accuracy while bump firing is next to impossible. While theoretically a bumping and firing stock could enable a shooter to fire as fast as a fully automatic weapon, they are a lot more prone to feeding issues and malfunctions, and since a standard AR 15 trigger or bolt carrier group and barrel aren't designed for such a high fire rate, they'll fail sooner.

Binary Triggers

The way binary triggers work is by firing a round both when the trigger is pulled and when it is released. As you can imagine, this can take a lot of shooting to get used to (hint: lean forward).

All of the best binary triggers on the market have a safety selector that has both a binary mode and a regular semi-automatic mode, which makes them a better overall tool than a bump firing stock, because you can select which mode, either binary mode or the other one you want to shoot in depending on what you're doing.

Because of the way a binary triggers work you'll never get up to the same rate of firing as with a full auto or a bump stock, but you can still feasibly pump out a couple hundred rounds per minute, so if you ever wanted to see how fast you can burn cash, you can probably do so faster with all of the best binary triggers than if you literally put cash on the ground and lit it on fire.

The Binary Trigger Market

Realistically, there's only one major player in the binary triggers market: Franklin Armory. As you'll see, we've also included Fostech, but for pretty much any platform besides the AR platform, your best bet is going to be the Franklin option. We did not even feel the need to include other brands on this list because of how dominant Franklin Armory binary trigger kits are.

1. Franklin Armory AR-C1 Trigger - Recommended

Our main recommendation is going to be the BFS ( binary firing system ) -III in all of it's different variations. While they're all the binary trigger, each Franklin Armory binary trigger has its own customizations and redesigns how this binary triggers work best with a specific platform of firearm. The AR-C1 has a trigger pull of 4.5 pounds, and a positive reset on the trigger release.

The safety has three positions - safe, semi-auto, and binary. It's a remarkably simple mechanism that works beautifully well. In fact, it makes me wonder why binary triggers aren't more ubiquitous. Other than costing a higher price, it seems like it would make sense for some AR manufacturers to ship models with a binary trigger from the factory.

The Franklin Armory AR-C1 is designed for (you guessed it), AR variants, and should actually work in both AR-15 models and AR-10s.

2. Fostech Outdoors Echo Sport Trigger AR-II (With Standard Curved Trigger)

For most of us who are thinking of putting a binary trigger on an AR-15, it's good to have at least one other option, and the best one is the Fostech Echo trigger. It's a bit different from the binary firing system III AR-C1, but it's pretty similar in security features and the metal trigger pull weight. You get a standard curved trigger and everything else from shoe to trigger spring is fairly standard.

Although, the standard curved trigger works well.

You get three shooting modes, but Fostech calls the binary mode "echo mode" because branding, but it's the same thing. Fostech calls the Echo a drop-in trigger, which is great, but I wouldn't expect it to be as simple as it sounds. Installation shouldn't be incredibly difficult but take it slow and follow the instructions very carefully.

Improper final installation can cause the weapon to unintentional discharge when you don't mean it to, and that applies to all of these binary trigger options.

3. Franklin Armory Binary Firing System -III AK-C1 Trigger (With Smooth Trigger Pull)

The AK-C1 is the Franklin Armory binary firing system for the AK platform, which is probably not shocking considering its name. This trigger is not as straightforward as the AR version, and it doesn't work with underfolding AK stocks, or Arsenal AK platforms. It also specifies that "some firearms may not be compatible with this trigger", which should be a given, I would think.

You get the same three position safety switch and the same basic options as the AR version. It has a smooth trigger pull and a clean release round for the trigger reset.

4. Franklin Armory BFS-III B&T C1

The majority of competition shooters who are looking for the best binary trigger are probably shooting AR 15 platform firearms, with the second spot most likely taken by those with AKs. That being the case, the first three binary triggers we talked about are probably the ones that are relevant to most of you, but there are several other models of the Franklin binary firing system that may be of interest.

Binary Firing System "B&T" is a reference to Brugger & Thomet, a Swiss firearm manufacturer. Among other firearms, they manufacture submachine guns under the APC line and the GHM line. These are available in a few different glock or pistol calibers.

Also, you should look at the caliber of AR15.

Despite these being sub machine guns, they do have semi-automatic carbine versions available for civilian purchase, and that's what these triggers are for. No real surprises here compared to the other Franklin triggers we've talked about, although they don't seem to stock as many of these because the wait times are much longer.

5. Franklin Armory BFS-III HK-C1

This is the Franklin binary firing system for a few of the popular HK rifles. The only thing that's really different with this trigger than the others is that it may take a gunsmith to do a professional installation on it. Basic functionalities are all the same with the three positions on the safety that constitute the binary trigger.

The difficulty here is that it's not as easy to get into the lower and swap out the trigger assembly on an HK as it is on an AR. All the things like the trigger spring and buffer spring that make the binary trigger work are a little bit more involved to install. This one is also a lot more expensive than the AR version.

6. Franklin Armory BFS-III CZ-C1

This Franklin Armory binary firing system is specifically for the CZ Scorpion and it works phenomenally well. The low recoil of the Scorpion (it shoots 9mm pistol rounds) keeps it manageable and extremely easy to shoot rapidly using the binary trigger. Everything else is the same as the rest of the triggers from Franklin.

With some weapons you only really get one round that's properly accurate and then the rest is just spray and pray, but with a little bit of shooting practice the recoil is low enough on this that you can consistently put your ammo where it's supposed to go.

You can also find very good options for your Ruger 1022, if you are looking for a 1022 trigger assembly.

Buying Guide

Why Do I Need This?

Range toy, gun enthusiasts, SHTF

I mean, you obviously need it, we just have to figure out why. The truth is, for most folks, this is just going to be a little range toy (little in size, not in price). If you're looking for something fun to do to spice things up at the range in between sighting in optics or shooting practice, this can be a fun range toy to do it with.

That said, there's a legitimate argument for preppers and those looking for a SHTF gun, or even just a truck gun. A binary trigger would serve you well in the same situations that a fully automatic AR 15 rifle would do so.

Semi-auto is going to be better in most defensive or combat situations, but there are definite cases where being able to rattle off more shots in quick succession is better. When combat is up and close, for example, and you need to put a combatant down before they can get in close enough with a knife or other weapon.

As a sheriff once said to me, "shoot to stop the threat", and if they're already close and you barely have time to get the rifle up before they're on top of you, dumping 3-5 rounds into them in the time it would normally take to get 1-3 is a better bet to keep you safe.

Full auto is also used as a way to manage and control enemy behavior during an engagement in the form of suppression fire. Chances are you won't have that much ammo to burn, but depending on who you're fighting, the psychological effects of sending just a few full auto shots downrange could be enormously effective because of greatly reduced split times and enhanced buffer spring.

What To Look For In a Good Binary Trigger

If you're not sold on Franklin Armory or Fostech and you want to keep looking for a binary trigger that's the right fit for your guns, here are a couple things to look for.

Basic Functionalities

Having some form of selector to go between a basic semi-automatic mode and binary mode shooting is critically important, unless you never intend to use the rifle for anything besides binary shooting.

In addition, you want to make sure that it replaces all the functionality of the trigger assembly that you're replacing. If the magazine release is part of the trigger assembly, then you need a binary trigger that has a magazine release as well.

Also pay attention to the binary trigger pull weight and how much pre travel, travel, creep, and over travel the binary trigger has. These basics shouldn't be ignored just for the novelty of being able to shoot really fast.

Things like too much trigger stacking can make it difficult to control your shots when you're already having to work harder than you're used to to control the rifle you're shooting. You also want the binary trigger to be solidly constructed so that it will function properly no matter what conditions it's brought into.

Easy or Professional Installation

There are many a trigger system that are advertised as having easy installation, and some of them really are simple to install. You'll want to make sure that if you're trying to save money you don't end up buying a trigger system that requires professional installation which then costs you more than if you had just bought a more expensive trigger system in the first place.

Having the trigger system properly installed is absolutely essential. And sure, sometimes it's as simple as disassembling the rifle as much as you would to clean it, popping out the pin, inserting the new assembly, putting in a slave pin and then popping the pin back in, but it can also be a lot more complicated depending on the lower receiver.

Why Is Everything Franklin Armory?

Honestly, the binary weapon system is still pretty niche, and no manufacturers have picked it up yet, which means that most guns don't even have a compatible system that can be installed on them. There are other aftermarket makers of binary weapon systems but Franklin has really nailed it so far.

I personally think that binary trigger are going to get new life over the next few years and Franklin Armory is going to have a lot more competition in just a short time for this hammer, mostly because there's not really a downside to having a binary trigger on your weapon.

Your safety switch still operates the same way and you just have a third option for either fun at the shooting range or a SHTF scenario. Franklin makes great triggers, but I'm excited to see more innovations in this space, particularly ones that work well with polymer lowers or a light weight BCG (bolt carrier group).

How Do Binary Triggers Compare to Bump Firing?

There are a few key differences between the two. Based on current laws and background in the US, the binary trigger system is actually on more shaky legal ground since it more flagrantly skirts the letter of the law than a bump firing device.

Since semi-auto is defined as one shot fired per squeeze of the trigger, you could argue that a binary trigger system is still semi-automatic - after all, each squeeze only results in one shot, and each release results in another. However, if you define a "pull" as a complete cycle of the trigger including the reset, then binary is neither semi nor fully automatic and could be an easier target for restrictions.

The bump stock is harder to argue against for several reasons - #1 it changes nothing about how the gun works and is just a creative way of getting it to do exactly what it's already doing, just faster, and #2, bump firing doesn't require a special stock; it's something you can do with anything that will bounce the rifle forward again with each shot.

That said, the binary trigger system is more useful and versatile in my opinion. Much like an M4 has a select option to go between semi auto and fully auto, you can equip your gun with the option to go from semi auto to binary, which is inferior in both shooting rate and accuracy (not to mention malfunctions) to fully auto but which gives you greater flexibility.

Final Thoughts

Binary triggers are awesome. Not only are they a lot of fun, but they offer legitimate functionality above and beyond a standard semi-auto to tactical shooters. As one YouTube comment I read joked, "we finally found that fully semi automatic I've heard so much about". Is there much utility for most of us to have a machine gun in our closet? Not really, which is why the best binary triggers make so much sense.

Above all, make sure it's compatible. Before you install it and take it to the shooting range, double and triple check everything from the lower to the bolt carrier group to the buffer spring. The last thing you want is a malfunction when you're working with a binary trigger system. Franklin has a separate model for each system they've designed a trigger for.

Whatever trigger system you end up getting, make sure you're not biting off more than you can chew on the install. Me, for example, if I have to swap out trigger springs and make sure the trigger pin size is correct and do all those details, I'm definitely going to screw something up, so I'd pay a higher price to get one that drops right in and I can get back to shooting.