Binary Triggers

Binary Triggers:

What Are They? What Do They Do?  Is That Legal?

 

Nearly everybody who shoots is fascinated by automatic fire… it looks cool, and it’s just plain fun. However, there are two problems with it for the average civilian shooter: owning an automatic weapon (while legal, under some circumstances) is highly regulated by the Federal Government and requires special licensing. The requirements for legal ownership of an automatic weapon include:

a) must be able to legally buy and own a firearm in the United States.
b) be 21 yrs of age or older.
c) pass a BATFE background check (which can take 8-12 months).
d) pay a transfer tax of $200 (this is a one-time fee, for each weapon, and is commonly called a “tax stamp”).

The other big problem for a purchaser of an automatic weapon is the price; fully automatic weapons can run in the tens of thousands of dollars, which is many times higher than the price of a semi-auto-only version of the same weapon. These two factors (legal requirements and price) make it difficult for most shooters to own such a gun.

While owning an automatic weapon is a challenge, shooters do have a much lower priced, and fully legal way of ‘simulating’ the rapid-fire capability that an automatic weapon provides… its called the binary trigger, and it’s a device (generally for AR-15 and AK-47 platforms) that many shooters have never heard of.

The key to understanding this whole issue lies in understanding the legal definition of an automatic weapon… which is defined as a weapon which fires more than one round for each manipulation of the trigger. This squares with most people’s understanding of how a ‘machine gun’ operates; when the trigger is pulled, the gun will fire and continue to fire until the trigger is released. A binary trigger, on the other hand, fires one round when the trigger is pulled… and another when the trigger is released. The release of the trigger is another manipulation of the trigger, making the system be defined as a semi-automatic weapon, and therefore, permissible without the licensing requirements of a fully automatic weapon. This is much different from a bump stock, where the shooter depresses the trigger, then the recoil of the gun allows the firearm to slide backward, reset the trigger, and slide forward against the user’s trigger finger, thereby firing the gun again.

Another important aspect of the binary trigger system is its price; while these trigger systems can retail in the ~$500 range, the cost of a semi-automatic rifle equipped with a binary trigger is much, much less than a fully automatic weapon. Also, it should be noted that binary triggers generally (at least on the AR-15 platforms) require a bolt that was machined for full auto fire; bolts that were machined for semi-auto only will not operate correctly with these triggers. Replacement of the bolt carrier group can add an additional $180-$200 to the cost, though even with this cost, the total is still far below that of a fully automatic weapon.

There are a few different manufacturers of binary triggers on the market, but the two largest are Fostech and Franklin Armory, both of which use a generally similar design. Both of these systems allow for selection of typical semi-auto fire (one round on the trigger pull, nothing on the release), as well the binary fire mode (fire on both pull and release of the trigger). Both also allow the shooter to “cancel” the second shot, by holding the trigger to the rear, and then applying the safety. This ability to select modes (between standard and binary) and also to cancel the second round make these trigger systems both safer and more versatile than other systems, some of which only allow binary mode. For both of these systems, a full trigger stroke is required; if the trigger is ‘feathered’ (meaning pulled just enough to release the first round, but not continued through the whole trigger stroke) then the sear may not be reset to allow the second round to be fired on the release. In that case, the trigger must be fully pulled again (with no round now benign fired on the pull), and then the sear is reset and the round fired on the release of the trigger.

The firing of a round on both pull and release means that this system allows fire at twice the speed at which the user can pull the trigger. With practice, a user can dump a full 30 round magazine in 5-6 seconds, perhaps even less. While it seems easy and obvious to do, rapidly applying a consistent and full trigger stroke can take a few magazines of practice to get used to.

While dumping a full magazine can be a lot of fun, it will (obviously) run through a lot of ammunition and will heat up the barrel quickly. Many AR systems will overheat and malfunction if 300-400 rounds are cycled through quickly, so care should be taken to allow the weapon to cool properly to avoid problems.

So other than ‘simulating’ automatic fire, what else can you do with a binary trigger? Competitive shooters have sometimes used binary triggers to help get 2 rounds onto (essentially) the same point of impact. This borders on impossible with a normal trigger, but with a quick manipulation of a binary trigger, the second round leaves the weapon before it has moved much from the recoil of the first round. This author tried that at a private range, using a Fostech Echo II trigger on an AR-15, shooting a freshly painted steel target (shown to the right).

All of those marks shown on the target are the result of 2-round bursts using that system; while the rounds did not land exactly on top of each other, each group was within about 1.5 inches, from a range of 50 meters.

So in summary, using a binary trigger system is a good way to simulate the rapid fire you can get from a fully automatic weapon, without the need for licensing and at a much more affordable price. It can also help you get a second follow-up shot to almost the same spot on a target, with a little practice. When using it, you do need to monitor your weapon, and not allow it to overheat… and you may need a lot of ammunition!

 

 

Select Fire Training Center now offers binary trigger packages for sale, and also has rental guns equipped with those triggers so you can try it yourself. Wednesday, March 8 2023 was our our first “Rapid Fire” night at the range. We’ll be adding more “Rapid Fire” nights soon. Be sure to join our private mailing list on the home page and try out a binary trigger for yourself, and see for yourself what it can do.