AR-15 Accessories the ATF Hates (And You Can Own)

AR-15 Accessories the ATF Hates (And You Can Own)

There’s a reason the AR-15 is known as America’s rifle. Owning a fighting capable individual rifle platform is seen as a trademark of American freedom and attempts to restrict this freedom are not met kindly by American gun owners.

As the primary government agency responsible for enforcing and interpreting firearms law, the ATF draws significant ire from freedom-loving gun owners. Of course, gun owners love to return the favor to dig in against the ATF whenever possible.

In celebration of that, we’ve assembled a couple of freely available AR-15 accessories we know that the ATF hates – either because they’ve come out (unsuccessfully) trying to rule against them, or because of the sheer absurdity and headache of having to rule on these items.

X-Products Can Cannon

If you’ve never heard of the Can Cannon by X-Products, you’ll be relieved to know that it is exactly what it sounds like. The Can Cannon is an upper receiver assembly that bolts on to your standard AR-15 lower. The “barrel” is a smooth-bore tube with a diameter perfect for loading your standard Coke or beer can.

The chamber portion of the Can Cannon accepts a 5.56mm blank round, but not will not fire a fully operable 5.56mm cartridge. Using the pressure of the blank cartridge, the projectile is launched out of the tube for a short distance. The result is an astoundingly fun version of the modern blunderbuss, designed to lob objects at things and create ridiculous amounts of fun for all involved.

So, of course, the ATF decided it had to be involved. In 2015, ATF declared that attaching a Can Cannon to an AR-15 lower turned the device into either a Short-Barreled Rifle or an Any Other Weapon (depending on whether the lower was a rifle or a pistol).

Their justification? The Can Cannon, despite not having any barrel to support a rifle cartridge being fired, could technically chamber and fire a live 5.56mm round. Of course, this would result in huge muzzle flash, trivial projectile velocity, and no accuracy to speak of (not to mention the product is clearly unconcealable). But this was enough to force a re-design of the product and re-work of all the product that had already been sold.

X-Products has since re-worked the Can Cannon to prevent the firing of a live 5.56mm round, again turning this from a dangerous short barreled rifle to a fun attachment made for launching soda cans, paint cans, tennis balls, and even a specially-designed grappling hook. Despite ATF’s intent to slow the product coming to market, it can currently be freely bought.


Franklin Armory Binary Firing System

Much to the chagrin of many gun owners, machine guns have been highly regulated for civilian ownership since 1934. Further, the Hughes Amendment of 1986 cut off the registry for any new additions, cutting off the list to those already registered and driving prices for registered machine guns sky high.

Naturally, illegal machine guns are treated very seriously, and the ATF enforces these laws severely.

However, where there’s a government regulation keeping people from exercising a right, there’s a genius engineer with a rebellious spirit and a keen eye for reading the exact letter of the law.

You see, the National Firearms Act defines a machine gun as any firearm which fires more than one round per any single function of the trigger. So, if you want to increase your rate of fire, but you can’t increase the number of rounds fired per trigger pull, what option do you have?

Well, since the release of the trigger is considered a separate function than the pull, you simply create a trigger that fires on both the pull and the release of the trigger. Such a trigger is referred to as a “binary” trigger and, incredibly, they have the blessing of the ATF – though the wording of the statute is such that the ATF wouldn’t have much choice but to rule that a pull and release of the trigger are two separate functions.

The Franklin Armory BFSIII is a drop-in trigger assembly that provides your Ar-15 with this binary fire function. The first two positions, safe and semi-auto, act the same as a typical AR-15 fire control group. The 3rd position (where full auto would be on an M4 or M16) activates “binary” mode. Pulling the trigger fires one round, while releasing the trigger fires a second shot. Mastering this method of fire can crank out rounds as quickly as 600-700 rounds per minute, faster than many machine guns.

At this point, ATF has not directly attacked binary firing systems. However, they have gone after another rate-altering device, bump-fire stocks. The ATF has published a notice stating their intent to alter their interpretation of current law and re-classify bump stocks as machine guns (despite prior letters from ATF stating that they did not fall into this classification).


AR-15 Arm Braces

When the Sig pistol brace first hit the market, it inspired a revolution of new, un-restricted firearms. Because of the tight restrictions of the National Firearms Act, any rifle with a barrel length below 16” is tightly regulated and requires jumping through lots of legal hoops to own.

The Sig brace is designed to act as a supporting brace to support the arm when holding up a short-barreled AR “pistol”. Replacing the stock, a firearm made with a shoulder brace was designed to be “fired from the hand” and so met the legal definition of a pistol, having no legal minimum length requirement.

Once this was discovered, manufacturers quickly started creating pistols with shoulder brace attachments. Although legally these firearms were meant to be fired from an unsupported position from the hand, the braces also functioned as stocks when pressed against the shoulder. In this way, shooters could have almost all the functionality of a short-barreled rifle without all the onerous restrictions and registration.

After initially approving the devices, ATF famously waffled back and forth on the issue of their use. First, they were legal, then they were illegal if used as a stock, then they were legal again. Finally, things have settled into a state where they’re generally left alone.

…Until recently, when ATF tried to prosecute a man for illegal possession of a “short-barreled rifle” when he was found in possession of an AR-15 pistol with a brace on it. In prosecuting the case, the ATF filed motions to keep their past determination letters (stating that braces did not turn a pistol into a rifle) from being used as evidence in the trial. Fortunately, the ATF suffered a rare defeat in this case.

There are several currently approved braces which are not considered stocks when attached to a pistol. The original Sig Brace was designed with a slot in the middle, and a reinforced velcro strap through which the arm can enter and be reinforced. Later, came devices like The Shockwave Blade which more closely resembled the design of a traditional stock, but with less surface area. The Tailhook brace, where one half of the rear brace folds down to make an entryway for the arm, has recently become popular.  With the popularity and success of all these models, there have been more arm braces, cheek rests, and buffer tube supports than could be named in any one model.



Imagine you’re working at the ATF’s Firearms Technology Branch, responsible for interpreting existing laws and applying them to firearms based on their technological capabilities and design features. Your job will consist of approving or disqualifying semi-auto conversions of open bolt machine guns, evaluating new arm brace designs, and making determinations on other policies such as awarding points for import determinations.

Then one day, you receive a request to evaluate a new AR-15 attachment. A polymer-injected replica of a pair of testicles attached to the bottom of a handguard. It is then your job to seriously evaluate this item on a functional level and decide what category it falls into.

Hilariously, this situation actually occurred to some employee of the ATF’s Firearms Technology Branch. One Reddit user (name no longer available) wrote to the ATF for a determination on the status of a Tac Sac if attached to an AR 15 pistol. As vertical foregrips on a pistol will turn the pistol into an Any Other Weapon, requiring registration under the National Firearms Act, the letter sought to find out if putting the Tac Sac on an AR 15 pistol would cause it to be re-classified as an Any Other Weapon.

Somehow funnier than the setup to the whole situation was ATF’s official determination. The official response letter deemed that the purpose of the attachment was clearly decoration, and if used as such would not cause the reclassification of any weapon. However, they caution that it is not advisable to use the attachment in any manner not intended by the manufacturer, as it may cause reclassification of the firearm.

In other words, it’s all good… as long as you don’t grab the Tac Sac.


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