…On May 7, 2021, the Attorney General signed ATF proposed rule 2021R-05, Definition of “Frame or Receiver” and Identification of Firearms. The goal of the proposed rule is to ensure the proper marking, recordkeeping, and traceability of all firearms manufactured, imported, acquired and disposed by federal firearms licensees….
See link below for more info. This is the first move against so-called \”ghost guns\”…
https://www.atf.gov/rules-and-regulations/definition-frame-or-receiver