Can I Register a Stripped Lower Receiver as a SBR?

If you have a stripped lower receiver you can register it as a SBR with the ATF. When you apply to make a SBR with the ATF you will be using the ATF 5320.1 Application to Make and Register a Firearm or the eForm 1. In order to apply using the ATF 5320.1 or the eForm 1 you will need to know the Overall Length (OAL) of the SBR that you are going to make. Note: the OAL of the SBR you are going to make is only an estimate on the ATF paperwork since you aren’t legally able to make the SBR to get the real OAL. Only once your ATF tax stamp is approved are you able to make your SBR, at that moment you can obtain the actual OAL.  If your actual OAL differs from your application you can simply send a letter to the ATF clarifying the actual OAL of your SBR.  The ATF will amend your approved tax stamp with this updated information. The last price of information that you will need for you application is the caliber that your SBR will use. If the caliber is already engraved on the lower receiver you will use that for your ATF application. But if your stripped lower receiver is engraved as “Cal Multi” or “Multical” or any derivative that doesn’t indicate an actual caliber then you will need to decide what caliber you will use with your SBR in the future. The caliber you choose will also need to be engraved on the stripped lower receiver if your stripped lower receiver doesn’t have an actual caliber engraved on it.  This will need to be done once you have received your approved tax stamp. However, if your barrel is conspicuously engraved with the caliber then the caliber doesn't need to be engraved on the lower receiver†.  You will also have to engrave your information on the stripped lower receiver, this is the information of the individual applicant, the trust applicant or the legal entity applicant. You can reference our ATF NFA Engraving Requirements Walk-Through Guide for more information on what you are required to engrave on your SBR.

†“Bureau of Alcohol, Tobacco, Firearms and Explosives.” ATF National Firearms Act Handbook (ATF P 5320.8) | Bureau of Alcohol, Tobacco, Firearms and Explosives, www.atf.gov/firearms/docs/guide/atf-national-firearms-act-handbook-atf-p-53208. Accessed 25 Aug. 2022 - Page 35.