I asked one of the Mods this, and it was suggested I post it here. As I understand it you can assemble a firearm with imported uppers and receivers that are made in the USA pursuant to 922r. Now when is it legal to sell it/them, and if sold does maker assume any liability if the weapon causes injury or death due to shoddy workmanship? I know there's guys on this board that assemble their own, so If you have any knowledge in this area please chime in. Here's all I could find on the ATF site FAQ...
http://www.atf.gov/firearms/faq/faq2.htm
Also pdf here; http://www.atf.gov/firearms/building_a_firearm.pdf
http://www.atf.gov/firearms/faq/faq2.htm
Also pdf here; http://www.atf.gov/firearms/building_a_firearm.pdf
A6) Does the GCA prohibit anyone from making a handgun, shotgun or rifle? [Back]
With certain exceptions a firearm may be made by a non-licensee provided it is not for sale and the maker is not prohibited from possessing firearms. However, a person is prohibited from assembling a non-sporting semi-automatic rifle or non-sporting shotgun from imported parts. In addition, the making of an NFA firearm requires a tax payment and approval by ATF. An application to make a machine gun will not be approved unless documentation is submitted showing that the firearm is being made for a Federal or State agency.
[18 U.S.C. 922(o) and (r), 26 U.S.C. 5822, 27 CFR 478.39, 479.62 and 479.105]