Under current federal law, you can shoulder an AR pistol equipped with a stabilizing brace. The ATF’s 2023 rule that would have reclassified braced pistols as short-barreled rifles was vacated in court, and the Department of Justice dropped its appeal in 2025. The National Firearms Act itself hasn’t changed, though, so certain parts and accessories can still turn your pistol into a regulated firearm no matter how you hold it.
Why Shouldering Is Legal Again
For years the ATF flip-flopped on whether pressing a stabilizing brace against your shoulder “redesigned” the brace into a stock and turned your pistol into an unregistered short-barreled rifle. A 2015 open letter said yes. A 2017 clarification said incidental shouldering was fine. Then in January 2023 the agency published Final Rule 2021R-08F, which used a multi-factor test based on weight, length of pull, and design features to sweep millions of braced pistols into the SBR category.
That rule is dead. The Fifth Circuit held that the ATF had exceeded its statutory authority and violated the Administrative Procedure Act by skipping proper notice-and-comment procedures.1Justia Law. Mock v. Garland, No. 23-10319 (5th Cir. 2023) The rule was vacated nationwide, and by mid-2025 the DOJ dropped its appeal. Without that rule, the ATF has no legal authority to treat shouldering a braced pistol as manufacturing an SBR. Your braced AR remains a pistol whether you fire it from your forearm, from your shoulder, or off a bench.
What Still Makes an AR a Pistol Under Federal Law
The reason shouldering doesn’t matter is that classification under the NFA turns on how the firearm was designed, not how you hold it. A “rifle” is a weapon designed or intended to be fired from the shoulder.2Office of the Law Revision Counsel. 26 USC 5845 – Definitions An AR pistol uses the same receiver as an AR-15 but pairs a barrel shorter than 16 inches with no shoulder stock. Because it was never designed to be shouldered, it’s a handgun.
That line is thin and worth respecting. A rifle with a barrel under 16 inches is a short-barreled rifle under the NFA, and possessing one without registration is a federal felony.2Office of the Law Revision Counsel. 26 USC 5845 – Definitions The court rulings killed the brace rule. They didn’t touch the definitions. Attach an actual rifle stock to a short-barreled AR and you’ve manufactured an SBR, whether you meant to or not.
Accessories That Can Still Get You in Trouble
Shouldering the brace is safe. Other modifications aren’t, and this is where owners most often stumble.
Vertical Foregrips
Adding a vertical foregrip to a handgun means, in the ATF’s view, that the weapon is no longer designed to be held and fired with one hand.3Bureau of Alcohol, Tobacco, Firearms and Explosives. Adding a Vertical Fore Grip to a Handgun If your AR pistol’s overall length is under 26 inches, bolting on a vertical foregrip reclassifies it as an “any other weapon” under the NFA, which requires registration.
There’s a workaround. If overall length exceeds 26 inches, the ATF generally considers the firearm too large to be concealed on the person, which is part of the AOW definition.2Office of the Law Revision Counsel. 26 USC 5845 – Definitions A vertical foregrip on a 26-inch-plus AR pistol sits in a gray area the ATF hasn’t classified as an NFA item. Measure from the muzzle (or a permanently attached muzzle device) to the farthest extension of the buffer tube or brace, and measure carefully.
Angled Foregrips and Hand Stops
Angled foregrips and hand stops aren’t treated the same way. The ATF distinguishes based on the grip’s angle relative to the bore: roughly perpendicular is “vertical,” angled forward is not. Angled grips and hand stops don’t trigger the AOW classification, so they’re a safer choice regardless of your pistol’s overall length.
Rifle Stocks
Attaching a real carbine or rifle stock to a short-barreled AR is the clearest way to manufacture an illegal SBR. There’s no ambiguity, no court ruling to save you. A stock is designed for shoulder firing, a barrel under 16 inches is short-barreled, and the combination requires an approved NFA registration before you assemble it.
Constructive Possession: The Parts Problem
You don’t have to bolt anything together to face charges. Under constructive possession, the ATF can argue that owning all the components needed to build an NFA firearm amounts to possession of that firearm, even unassembled. Own an AR pistol lower, a short barrel, and a rifle stock with no NFA registration on file, and a prosecutor can claim you possess the parts for an unregistered SBR.
The risk is highest when the parts have no lawful use in any other configuration. If you also own a 16-inch or longer upper receiver that would legally pair with the stock and lower, that undercuts the argument because the parts have a legal home. It isn’t a legal shield, but it makes the government’s case harder to build.
What a Violation Actually Costs
Possessing an NFA firearm not registered to you is a federal felony.4GovInfo. 26 USC 5861 – Prohibited Acts That covers an unregistered SBR, a firearm you manufactured without an approved Form 1, and one transferred to you outside NFA procedures.
Conviction carries up to 10 years in federal prison and a fine of up to $10,000 under the NFA’s penalty provision.5Office of the Law Revision Counsel. 26 USC 5871 – Penalties The general federal sentencing statute also allows fines up to $250,000 for any felony, which can apply on top of or in place of the NFA fine.6Office of the Law Revision Counsel. 18 USC 3571 – Sentence of Fine The firearm is forfeited, and a federal felony conviction ends your right to possess any firearms going forward.
State Law Can Override the Federal Answer
Federal law is only half the picture. A handful of states ban AR-style pistols outright or classify them as assault weapons based on features like threaded barrels, pistol grips, or detachable magazines. Some states define short-barreled rifles differently than the NFA does. Several states and the District of Columbia cap handgun magazine capacity, most commonly at 10 rounds.
Your braced AR pistol can be perfectly legal federally and still violate your state’s assault weapon statute. Before you build, buy, or travel with one, check the laws in every jurisdiction where you plan to possess it, including city and county ordinances that go further than state law.