ATF Final Rule 2021R-08F “Factoring Criteria for Firearms with Attached Stabilizing Braces”

Updated November 9th, 2023

On Wednesday, November 8th, 2023 U.S. District Judge Matthew Kacsmaryk ordered a nationwide preliminary injunction which prevents the ATF from enforcing the final rule 2021R-08F, “Factoring Criteria for Firearms with Attached ‘Stabilizing Braces,’”.

This means that the rule and information below no longer applies. It is once again legal for you to have an AR pistol with a stabilizing brace or pistol brace and you do not have to register it as a Short Barreled Rifle (SBR) with the ATF.

Original Post
The following information has been edited and the links to the former ATF eform 1 web page were removed.

The ATF has published the Factoring Criteria for Firearms With Attached “Stabilizing Braces” on the Federal Register. All individuals that have a firearm with a stabilizing brace that meets the requirements must register it as a Short Barreled Rifle (SBR) within 120 days from January 31st, 2023. The firearm must be registered as an SBR no later than Tuesday, May 31st, 2023. After this date, if caught, it will be a federal felony to possess the firearm.

  • The firearm with stabilizing brace must have been owned on or before January 30th, 2023 to receive the Stamp Tax exemption.
  • If you wanted to have the new SBR in your NFA Trust and receive the Tax Stamp exemption, it must have been in the Trust on or before January 30th. 2023. If it was not in the NFA Trust, you must register it as an individual or pay the $200 Stamp Tax to put it in your NFA Trust.

All Micro Roni or MCK (Micro Conversion Kit) made by CAA USA, or other similar kits made by other manufacturers, which have a Stabilizing Brace attached where a pistol such as Glock, or any other pistol is inserted is considered an SBR. This means if you want to continue to use these items you are required to register the pistol, in this example a Glock, as an SBR. Yes! as stupid as it sounds, it is true.

See more information:

Commercially available firearms equipped with a “stabilizing brace” that are short-barreled rifles
Common weapon platforms with attached “stabilizing brace” designs that are short-barreled rifles

For those that do not want to register the firearm with stabilizing brace as an SBR, you have four (4) options, which must be completed no later than Tuesday, May 31st, 2023.

  1. Permanently remove or alter the “stabilizing brace” so that it cannot be reattached and thereby removing it from regulation as a “firearm” under the NFA.
  2. Remove the short barrel and attach a 16-inch or longer rifled barrel to the firearm thus removing it from the provisions of the NFA.
  3. Turn the firearm into your local ATF office.
  4. Destroy the firearm.

NOTE: No letter, email, or other information was sent to Federal Firearms Licensee (FFL) dealers/manufacturers. The Bureau Of Alcohol, Tobacco, Firearms, and Explosives (BATFE/ATF) only posted this information on its website.

On January 13, 2023, the Attorney General signed ATF final rule 2021R-08F, “Factoring Criteria for Firearms with Attached ‘Stabilizing Braces,’” amending ATF’s regulations to clarify when a rifle is designed, made, and intended to be fired from the shoulder. Pursuant to ATF Final Rule 2021R-08F, the Attorney General has authorized certain persons tax-exempt registration of firearms they own or possess at the publication of the rule that are: 1) equipped with a stabilizing brace; 2) meet the definition of “rifle” under federal law; and 3) have a barrel or barrels less than sixteen (16) inches in length.

Read more information on the ATF’s website about Factoring Criteria for Firearms with Attached “Stabilizing Braces”.

We have taken some important from the ATF Frequently Asked Questions that you need to understand.

3. If I chose to register a stabilizing-brace equipped SBR, do I have to pay the NFA registration tax?
No, provided you submit your NFA registration application to ATF within 120 days of the publication of the final rule. See questions 13 and 14 below for additional information on the provisions in the final rule providing for tax forbearance on NFA registration applications.

4. Does the ATF Have a list of specific “braces” that qualify in making a pistol into a short-barreled rifle (SBR)?
No. ATF regulates firearms as defined by the Gun Control Act of 1968 and National Firearms Act, and therefore, in general, ATF does not regulate accessories such as “stabilizing braces.” ATF will provide examples of both commercially available firearms sold with “stabilizing braces” and common weapon platforms equipped with “stabilizing braces” that are considered SBRs at https://www.atf.gov/rules-and-regulations/factoring-criteria-firearms-attached-stabilizing-braces.

6. What are the compliance options for an individual (non-licensee) in possession of a firearm equipped with a “stabilizing brace”, which is a short-barreled rifle(SBR), after the effective date of the final rule?
• Submit through the eForms system an Application to Make and Register a Firearm, ATF Form 1 (EForm 1) within 120-days from the date of publication in the Federal Register.
• Permanently remove or alter the “stabilizing brace” so that it cannot be reattached and thereby removing it from regulation as a “firearm” under the NFA.
• Remove the short barrel and attach a 16-inch or longer rifled barrel to the firearm thus removing it from the provisions of the NFA.
• Turn the firearm into your local ATF office.
• Destroy the firearm. For more information go to How to Properly Destroy Firearms | Bureau of Alcohol, Tobacco, Firearms and Explosives (atf.gov).

10. Once the firearm is registered as a short-barreled rifle (SBR) can I remove/change the “stabilizing brace” or attach an item marketed as a stock? If so, am I required to notify ATF in advance?
Yes, the firearm is registered as an SBR, and you can change out the “brace” device or stock for a different brace or stock. You do not need to contact ATF/NFA because changing the brace/stock does not change the configuration of the SBR. However, if the length of the firearm has changed you will need to notify the NFA Division.

11. If I no longer want an SBR and I remove the “brace”, do I need to contact the NFA to un-register my SBR with an attached “Stabilizing Brace”?
It is not a requirement to remove your SBR from the NFRTR; however, ATF highly recommends you notify the Government Services Branch (GSB) of the National Firearms Act Division to remove the firearm from the NFRTR registry. All NFRTR updates should be emailed to [email protected].

12. Can I register my firearm with a “stabilizing brace” to my Trust?
Yes, however, the firearm would have needed to be owned by the trust prior to the date the final rule is published in the Federal Register. Evidence that the firearms was in trust should be provided with the registration document.

13. Is there a limit of how many firearm with a “stabilizing brace” that I can register as SBRs for free during the tax forbearance period?
The tax forbearance only pertains to the firearms with an attached “stabilizing brace” in your possession at the time the final rule is published. There is no limit on how many you may register, but owners in possession of these types of SBRs must register within 120-days from the date of publication in the Federal Register.

14. If my SBR is made after the date of publication of the final rule, can I still register it as an SBR for free during the tax forbearance period?
No. The registration options available to a possessor of such firearm applies to those possessed on the effective date of the final rule.

15. If I attach my “stabilizing brace” on a rifle with a 16″ barrel, will the firearm fall within the purview of the NFA?
Generally, no. A rifle with a barrel (rifled) of at least 16 inches would not be an SBR under the NFA regardless of whether it incorporates a “stabilizing brace” or traditional shoulder stock. Note, the firearm would need to retain an overall length of at least 26 inches and not fall into other NFA categories. Firearms with an attached “brace” device may be submitted to FATD for a determination.

21. What are my options if I want to sell my “registered” firearm as an SBR with or without the brace?
If you are selling the firearm as an SBR, which is “registered” in the NFRTR, an ATF Form 4, Tax Paid Transfer would be required to complete the transfer.

22. After the 120-day tax forbearance expires, can I continue to possess an unregistered firearm with an attached “stabilizing brace” that is a short-barreled rifle (SBR)?
The National Firearms Act requires registration of all SBRs. A person may not possess an unregistered SBR.

23. Can I possess a pistol and unattached “stabilizing brace”?
An NFA firearm need not be assembled to be regulated as such. Whether a person may be in constructive possession of an NFA firearm depends on the facts of a particular case.

24. What are the consequences if I intentionally choose not to register my firearm with a “stabilizing brace”, which is an SBR, and keep it?
Unlawful possession of an unregistered SBR is punishable by up to 10 years’ imprisonment or $10,000 in fines, or both. (26 U.S.C. 5861(d), 5871).

25. Prior to and after the expiration of the 120-day tax forbearance, can I continue to possess my SBR equipped with a “stabilizing brace” if I have timely submitted my application to register my firearm?
Yes. Provided you are not otherwise prohibited from possession of a firearm under Federal or State law, you may continue to lawfully possess your SBR while your registration application is pending with ATF. While your application is pending, you should maintain proof of submission as evidence of continued lawful possession.

27. Once the firearm is registered, am I required to mark the firearm since I manufactured a short-barreled rifle (SBR)?
If the SBR equipped with a “stabilizing brace” is registered within the 120-day tax forbearance period, the possessor is allowed to adopt the markings on the firearm. The maker’s marking exception is only applicable to firearms that are registered pursuant to the final rule. If the firearm is a personally made firearm, the possessor must mark in accordance with 27 CFR 478.92 & 479.102 prior to submitting the E-Form 1.

28. Can a short-barreled shotgun be registered during the 120-day tax forbearance period?
No. The forbearance period only applies to SBRs.