Franklin Armory BFSIII Binary Trigger [Review]
The Franklin Armory Binary Trigger allows a shooter to simulate full-auto fire without the expense and NFA restrictions of a truly fully-automatic lower. Find out more about this cool piece of engineering (and see why it might be going away forever).
Professional writer & editor. Competitive shooter. Hobby-level gunsmith
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What is a Binary Trigger?
A binary trigger is a drop-in replacement trigger that allows you to simulate full-auto fire in a semi-automatic weapon. This thing dramatically increases the fire rate of a semi-automatic AR-platform firearm. Is it as fast as a true fully-automatic weapon? I don’t exactly have an M4 on hand to compare, but looking at my splits with shot timer, I’m getting about 400 rounds per minute (obviously with a 30 round mag) which is a little under half the fire rate of a true full-auto rifle. That being said, it is a marked increase over a regular semi-automatic rifle, so you are getting what you pay for. It’s a $400 solution to a $4,000 (minimum) problem, but for all that it works damn well.Installation
I’ve installed, swapped, changed, replaced, and repaired literally hundreds of triggers in my day, and this one was neither the easiest nor the hardest one to work on. I would say if you can follow our guide to building an AR-15 lower, you’ll be fine. It took me about thirty minutes, and most of that was getting the previous trigger out of the gun I tested it in (and finding my freaking punches that rolled under my bench at some point).
How Does it Work?
Binary triggers like the Franklin Armory BFSIII work by releasing the sear on the pull and release of the trigger when in binary mode, though you can also easily flip the three-way fire selector to regular semi-auto. This effectively doubles your fire rate and can give you some very close two round groups, to the point where I could land two hits in the A-zone at 25 yards with one trigger pull. Here’s Franklin Armory’s take:“The revolutionary Binary Firing System™ will be appreciated by three gun competitors, tactical shooters, and recreational enthusiasts. It features a three position selector that allows the user to switch from Mode 1 for Safe, Mode 2 for traditional Semiautomatic Mode, or Mode 3 for Binary Mode. In Binary Mode, the firearm will discharge one round with every function of the trigger whether a pull or a release. A user can negate the round that would otherwise be fired during the release function by simply moving the selector back to Mode 2 and then safely releasing the trigger.”
Which of course sounds great, but how does it perform in the real world?Shooting the Franklin Armory Binary Trigger
So, with that in mind, how does this thing really shoot? Pretty well, it turns out. Now, don’t get me wrong, it doesn’t feel as nice as a say, a good Geissele or Timney trigger, not even one you can get for half the price of the BFSIII.Prices accurate at time of writing
Prices accurate at time of writing
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Practical Applications
In short… eh? Maybe. Kinda. It depends. But not really, no. When I say it depends, I say that because it depends on whether or not you’re actually getting it to defend yourself, or you’re trying to convince a spouse to let you spend $400-$500 on one by extolling its practical uses. If you haven’t trained with a full-auto weapon, it’s going to be more of a hindrance than a help in almost any practical defense situation. I suppose, yes, if you need to suppress an intruder’s position so a family member can flank them and take them out, maybe it’s better? You could at least make the argument. But that situation has happened a grand total of zero times in a home defense scenario. You are not John Wick.

Parting Shots (and another warning)
Overall, I quite like the BFSIII, I think it’s a great piece of engineering, and it absolutely does what it claims to do. I take issue with some of Franklin Armory’s marketing on what this thing is actually good for, but I think that’s more of a case of wishful thinking on their part than it is actual malice or an attempt to deceive anyone. All in all, it’s a great little piece of kit, American made, and it’s fun as all get out. It’s also one of the best ways to turn money into noise at the range, and that alone makes it worth the cost of admission. Now, I do have to again bring up the fact that there’s legislation being bandied about right now that would ban these devices. So check your local laws and make sure you’re not committing a felony. But as long as it is legal for you to own, I highly recommend it–it’s just too fun not to have! Especially if you pair it with a .22 LR AR-15 so that all of that binary shooting doesn’t run you bankrupt. Take a look at our Best AR-15 in .22LR article for some great recommendations!Prices accurate at time of writing
Prices accurate at time of writing
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25% off all OAKLEY products - OAKLEY25
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