FAQ

Are 80% or unfinished receivers illegal?

No, receiver blanks that do not meet the definition of a "firearm" are not subject to regulation under the GCA. The ATF has long held that items such as receiver blanks, "castings" or "machined bodies" in which the fire-control cavity area is completely solid and un-machined have not reached the "stage of manufacture" which would result in the classification of a firearm per the GCA.

See comparison examples:

Receiver Blank Comparison Examples