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Definition of “Frame or Receiver” and Identification of Firearms

On April 11, 2022, the Attorney General signed ATF final rule 2021R-05F, Definition of “Frame or Receiver” and Identification of Firearms. The goal of the final rule is to ensure the proper marking, recordkeeping, and traceability of all firearms manufactured, imported, acquired and disposed by federal firearms licensees.

The rule will go into effect August 24, 2022; 120 days from the date of publication in the Federal Register.

Read the final rule in the Federal Register

ATF eRegulations

Summary

On April 11, 2022, the Attorney General signed ATF final rule, Definition of “Frame or Receiver” and Identification of Firearms, amending ATF’s regulations by removing and replacing the regulatory definitions of “firearm frame or receiver” and “frame or receiver” using examples and diagrams to clearly convey what is a “frame or receiver,” amending the definitions of “firearm” and “gunsmith,” providing definitions of terms such as “complete weapon,” “complete muffler or silencer device,” “privately made firearm” and “readily,” and amending regulations on marking and recordkeeping.

Read the full summary

Related Resources

Questions and Answers

A PMF is a firearm, including a frame or receiver, completed, assembled, or otherwise produced by a person other than a licensed manufacturer, and without a serial number placed by a licensed manufacturer at the time the firearm was produced. The term shall not include a firearm identified and registered in the National Firearms Registration and Transfer Record pursuant to chapter 53, title 26, United States Code, or any firearm manufactured or made before October 22, 1968 (unless remanufactured after that date).

FFLs must record “Privately Made Firearm” or “PMF” as the manufacturer in the A&D record and ATF Form 4473. If an FFL is remanufacturing a PMF, see question 33 for marking requirements.

No. Marking serial numbers on PMFs is a “customization” and a licensee’s return of a firearm, received solely for repair or customization, to the person from whom it was received does not require an ATF Form 4473 pursuant to 478.124(a) nor a NICS background check. However, licensees must record the acquisition and disposition of the PMF in the licensee’s A&D record.  

A licensee is not required to mark a PMF received for same day adjustment or repair that the licensee returns – on the same day as it was received – to the person from whom it was received. Furthermore, a licensee is not required to record an A&D entry, nor execute an ATF Form 4473, nor run a NICS background check when such firearm received under these conditions is returned to the customer from who received. 

Yes. A PMF acquired by a licensee, for any purpose, that is returned to a person other than the person from whom it was received requires the licensee to mark the PMF appropriately (if not already marked pursuant to 478.92(a)(2)), record the PMF as an acquisition and disposition in their A&D record, record the transaction on an ATF Form 4473, and conduct a NICS background check before transferring the firearm. 

Contact Us

For questions regarding the application of the final rule, contact the Firearms Industry Programs Branch at FIPB@atf.gov.

For technical questions regarding firearms, contact the Firearms and Ammunition Technology Division at fire_tech@atf.gov.

For questions regarding the rulemaking process, contact the Office of Regulatory Affairs at ORA@atf.gov.

Last Updated: January 28, 2026

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