ATF quote:

"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. The following is a summary of the final rule, but is not intended to be relied on when complying with the requirements of the final rule:

unquote

https://www.atf.gov/rules-and-regula...ceiver/summary