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Post updated on October 1st, 2021. For clarity on Any Other Weapon (AOW) & folding stabilizing braces in regards to overall length measurements.

Last Friday, Prince Law Office Blog reported that ATF released a new letter addressing how you are suppose to measure an overall length of a firearm equipped with a stabilizing brace.  An individual contacted the law office in which the individual had received a letter from the ATF which was a response to a question requesting the correct method to “measure a firearm with a ‘stabilizing brace’ and folding adapter.”  Prince Law Office states, “It was explained that the correspondence was sent in the form of an email over a year ago and that the person had received a response via email shortly after it was sent. This letter was unsolicited and came over a year after the original request and response.” 

The purpose of this post is to break through all the legal jargon and advised you how to properly measure the length of an AR pistol.  Let’s break this letter down and get to the nitty gritty on how to properly measure an AR pistol.

First here is the legal Jargon. 

The Letter States:

[Firearms Technology Industry Services Branch] FTISB has previously determined that “stabilizing braces” may be assembled on firearms as accessories… In contrast to stocks on rifles or shotguns…”stabilizing braces” are merely accessories and not relevant to the classification of a “pistol” under the statutory definition. That is, a folding stock on a rifle or shotgun is included in overall length measurements because the firearm must be “designed or redesigned….and intended to be fired from the shoulder” to be so classified. The stock is therefore an essential element in the statutory definition.

Makers also create an artificial overall length measurement by attaching a folding stabilizing brace. Such a measurement would be problematic because the firearm could avoid classification as an “AOW,” yet retain the conceivability and remain fully functional. Measuring a folding (or telescoping) stabilizing brace would therefore undermine the comprehensive statutory and regulatory design of the GCA and NFA.…The measurement of a folding or collapsible stabilizing brace in the overall length of a firearm creates an artificial overall length that would permit a maker to avoid classification as an NFA “firearm” without a viable design purpose or legal justification.

Alright that is the legal speak from the ATF concerning stabilizing braces. Now, let’s break through it all and get a clear understanding measure AR pistol length.

What does this mean?

Let’s take the the first part of the statement from the ATF and break it down. ATF is saying your shockwave brace or SB Tactical brace on your AR Pistol is not considered in the overall length of the firearm. That the “stabilizing brace” is an accessory to the firearm and not integral to the AR pistol. Since the brace is not integral to the firearm and is consider an “accessory” it is not consider in the overall length of the firearm. 

The ATF continues to explain that if on a rifle or shotgun it would be classified as apart of the overall length of the firearm. That is because the rifle or shotgun is “designed or redesigned…and intended to be fired from the shoulder.” In basic terms means that the folding stock is apart of the design of the shoulder fired rifle or shotgun and  therefore is apart of the overall length of the rifle or shotgun. 

What is the proper way to measure your AR Pistol now?

With the this new information from the ATF the proper way to measure your AR Pistol is from the base of the buffer tube to the muzzle or from the base of the buffer tube to the end of the muzzle device if permanently attached. 

How do we measure folding stabilizing brace? 

If you have a folding stabilizing brace it must be measured in the folded position to find out overall length.  The ATF states “Such a measurement would be problematic because the firearm could avoid classification as an “AOW” yet retain concealability and remain fully functional. Measuring a folding stock (or telescoping) stabilizing brace would therefore undermine the comprehensive statutory and regulatory design of the GCA and NFA.” 

Since the rifle platform in its folded position can cross into grey areas on what is considered an NFA item or non-NFA item the rifle must be measured from the folded position to find out overall length. 

Why it matters

Why this is important you might ask? It is because with this interpretation it leaves the potential of many firearms owners not being in accordance with National Firearms Act. It would call into question anyone who had built an rifle or AR pistol with a stabilizing brace with a vertical grip. 

Before this interpretation change firearm owners would include the stabilizing brace as apart of the overall length of the firearm in figuring out if they could use a vertical grip versus a hand stop. Rifles had to be an overall length of 26 inches to be able to use a vertical grip. If not a shooter would have to use an angled grip on their AR pistol. Unless, that weapon was registered under the NFA with a SBR tax stamp. Then, a foregrip was allowed.

Now, with this change of overall length interpretation many AR pistol owners may have either built an SBR (short barreled rifle) or a AOW (any other weapon) unintentionally that would be now subject to the NFA and GCA. The AOW classification would be in regards to the folding stabilizing brace. Those owners would have to adjust their builds to fall in accordance with the NFA to be in compliance or face potential legal ramifications.

To fully understand, it is important to look at the definitions. The term “any other weapon” is defined to include

…any weapon or device capable of being concealed on the person from which a shot can be discharged through the energy of an explosive…Such term shall not include a pistol or a revolver having a rifled bore… (emphasis added).

The term pistol is defined as

A weapon originally designed, made, and intended to fire a projectile (bullet) from one or more barrels when held in one hand… (emphasis added).

ATF has taken the position that once a vertical foregrip has been added to a firearm, it is no longer designed to be fired when held in one hand, removing it from the definition of a pistol, even though ATF previously lost this argument before the Ninth Circuit in U.S. v. Fix, 4 Fed. Appx. 324 (9th Cir. 2001).

Less than 26 inches Vs. Greater than 26 inches

The ATF has historically considered overall length of 26 inches the breaking point for concealability. So here is the rundown. If the overall length of the firearm is under 26 inches, it places the firearm in a category to be regulated by the NFA. If the overall length is over 26 inches, it would remove that firearm from that category to be regulated by the NFA.

Now, let’s break this down into the confines of AR pistol. If you have an AR pistol with the overall length under 26 inches it would be consider an Short Barrel Rifle (SBR) and would fall under the NFA. Which means you would need a tax stamp to put a vertical grip on your AR pistol. If you have an AR pistol with an overall length greater than 26 inches it is not consider concealable for the purpose of the SBR definition by ATF. Again, which allows you to put on angled grip or vertical grip on that rifle. (If there was evidence it could be concealed by a person it would fall under the SBR guidelines). By adding a vertical grip to an AR pistol with the overall length under 26 inches turns it into a “firearm” no longer designed to be fired from one hand, per ATF.

Conclusion

At the end of the day what the ATF is stating that firearms equipped with stabilizing braces must measure over 26 inches to have a vertical grip. The proper way to measure for 26 inches is from the base of the buffer tube to the muzzle or muzzle device( if the muzzle device is permanent aka penned and welded). For a folding stabilizing brace it must be measured from the folding of the brace to the muzzle or muzzle device( if the muzzle device is permanent). If the overall length length results in less than 26 inches it becomes an AOW and is subject to the National Firearms Act.

What do you think of the new interpretation? Will you have to remove your vertical grip or buy a hand stop now? Let me know in the comments below. 

Thanks for Reading 

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13 Comments »

  1. what about the length of pull on an AR pistol? If I add a Law Tactical folding adaptor on my AR pistol it increases the length of pull with the SB tactical brace fully extended, would this make it an NFA firearm?

  2. The NFA further defines the term “any other weapon” (AOW) as::

    … any weapon or device capable of being concealed on the person from which a shot can be discharged through the energy of an explosive, a pistol or revolver HAVING A BARREL WITH A SMOOTH BORE designed or redesigned to fire a fixed shotgun shell, weapons with combination shotgun and rifle barrels 12 inches or more, less than 18 inches in length, from which only a single discharge can be made from either barrel without manual reloading, and shall include any such weapon which may be readily restored to fire. SUCH TERM SHALL NOT INCLUDE A PISTOL OR REVOLVER HAVING A RIFLED BORE, or rifled bores, or weapons designed, made, or intended to be fired from the shoulder and not capable of firing fixed ammunition. 26 U.S.C. § 5845(e).

    AR Pistols cannot be classified as an AOW regardless of length, period.

    • I agree with you. In the determination letter from the ATF they state that folding stabilizing braces are seen as problematic. The ATF sees it that was because it could avoid the classification off an “AOW” yet retain concealability and functionality of the weapon. They believe it undermines the regulatory designs of the NFA and GCA. Those are their words not mine brother. From the letter.

      I agree with you. That it can’t fall under that determination. Yet, the back and forth ATF who doesn’t have clear understanding of their own policies makes that claim.

      Now, could I have phrased it and explained it better? Yes, I could have. I take the blame for not doing that. That is an error on my fault that I will correct in the article. Thank you for bringing it to my attention.

  3. This is confusing.

    The ATF in the new 6/2021 requirements on AR Pistols with/brace says (from Worksheet 4999)
    “The weapon must have an overall length between 12 and 26 inches.” To be a non NFA AR pistol.

    But you state “If you have an AR pistol with the overall length under 26 inches it would be considered an “AOW” and fall under the NFA. ”

    Both can’t be correct as I understand it. Please explain.

    • My apologies for the late response. First, off I was wrong in my usage of AOW in my article and I didn’t explain it well. Thank you for bringing it to my attention. I read the section of the article you mentioned and corrected it.

      So, to the prerequisites of worksheet 4999. For your AR pistol to be even consider it must weigh in @ 64 ounces unloaded and between 12 and 26 inches without the stock. Then, from there you get into the point system and the defining points to the characteristics of your brace.

      Normally, a AR with an length between 12 and 26 inches would fall into SBR range. With an SBR you would have to register it under the NFA and pay the $200 tax stamp. That’s if you where looking to put a normal stock on it.

      The part about “AOW” from the ATF statement was in regards to a folding stabilizing brace. In which the ATF believes that it could avoid evaluation as an “AOW” while retaining concealability & functionality of the weapon. In turn that would undermine the NFA & GCA, per the ATF. So, the “AOW” reference is in regards to folding stabilizing braces, specifically. If it is considered an “AOW” it will fall under the purview of the NFA. Which I should have clarified in the article originally.

      I was using “AOW” and “SBR” interchangeably which was incorrect and I apologize for that.

      The whole point of worksheet 4999 is to see if your pistol brace falls under their traditional definition of an accessory your AR pistol. Or to see if the pistol brace you currently uses blurs the lines from pistol brace to stock. If your brace has too many points on worksheet 4999 it will be considered a stock and would fall under the NFA as an SBR. Which would in turn mean you would have to register it and pay for a tax stamp to keep it in its current configuration. The whole point of worksheet 4999 and the new classification being put forth by the ATF is to crackdown on illegal SBRs, because they believe people are using the pistol brace classification as a loophole to have SBRs without having them. I hope that helps if you have any other questions. Feel free to him me up.

  4. why does it have to be measured from the buffer tube? if you attach a brace, the brace doesn’t always just come right off. you’d think the back of the brace would be considered “if” it was attached and was longer than where the buffer tube ends. this could be harder to conceal per them since the brace is making the weapon bigger.

    now what about a pistol that doesn’t have a buffer tube like a AK pistol? if you add a buffer to a AK pistol, you again make the weapon bigger and harder to conceal but is adding a buffer tube to a weapon that doesn’t need it legal?

    so in the end, take a AK pistol, add a buffer tube, add a pistol brace, and you now have a weapon with a OAL of +26″. still legal then for a grip or no grip and just have a really big pistol?

    • Hey Scott,
      Good question. Idk why the ATF chooses to include the buffer tube and not the brace. I’m not sure who made that executive decision within the ATF’s technology department but someone did. So you would measure from the buffer tube because it’s attached to the lower and is key to the function of the AR Pistol so it gets added. You would measure from the buffer tube to the threading of the barrel or the muzzle device if pinned and welded to calculate that 26” inches in overall length for a vertical grip. Anything under would be an angled grip. Yes, there is a one of exception that comes to mind and I think it’s the shockwave Brace can be added to the overall length because it can’t be removed. I believe that is an exception. If I’m wrong the internet will blast me for it. Lol Gotta love it.

      When it comes to AK pistol you would be measuring from back where the brace would fold to the front of threads of the barrel or to the muzzle device if it was pinned and welded. From there you would calculate your 26” inches. If it’s over you can put a vertical on it. If it’s under you can do an angled foregrip to stay in compliance. I hope that helps. If you have more questions hit me up. I will do my best to answer them all. 🤙🏾

  5. Okay, IF the AR pistol, with brace and folding, it is a pistol still IF there is NO vertical foregrip? I keep seeing that part out. It is the vertical foregrip issue that makes it an SBR right? If I have a folder ar pistol with a brace that is under 26″, has a hand stop (not a vertical grip) it is still a pistol right. The vertical fore grip in my understanding is what makes it an SBR….

    • The whole letter is the response from the ATF on the question of how do you measure overall length of an AR pistol and when is it legal or illegal to place one on your AR pistol and still be compliant. Which I think is dumb but is neither here nor there. To answer your question for your rifle AR Pistol to be able to use a vertical foregrip it must be 26” inches in overall length. That length is measured from the buffer tube to the threading of the barrel or to the muzzle device if pinned and welded. Meaning you can use a vertical grip. If it is under that you must use an angled foregrip to be in compliance. Now, if it’s a folding stock you will measure from where the stock folds/pivots to the threads of the barrel or muzzle device if pinned and welded. Now, if it measures 26” inches or greater you can slap a vertical grip on there. If not greater than 26” inches you can slap a angled foregrip on their and be good. I’m assuming the same rule applies for AK pistols as well.

  6. Good article about lengths, but you have some confusion with the regulations in this article.
    You need to rework the last section : Less than 26 inches Vs. Greater than 26 inches

    The SBR definition is not related to overall length. An SBR is just a rifle with a barrel length under 16″.
    What you meant to say in that section was an AR pistol under 26″ overall length with a vertical foregrip would place it under the AOW classification and would then fall under the NFA.
    Also, you got the wording backwards in the last sentence of that section. It should say: By adding a vertical grip to an AR pistol with the overall length OVER 26 inches turns it into a “firearm”. Not “under” 26 inches.
    Other than that…nice article.

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