Here is what the ATF has to say on this subject:
Reference:
http://www.atf.gov/firearms/faq/faq2.htm#a6
(A6) Does the GCA prohibit anyone from making a handgun, shotgun or rifle?
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]
******************************************************************
Here are all of the references cited by the ATF in the above paragraph
******************************************************************
Reference:
http://www4.law.cornell.edu/uscode/
18 U.S.C. 922(o) Applies only to NFA (Machine Guns, etc) Weapons
18U.S.C. 922(r)
(r) It shall be unlawful for any person to assemble from imported parts any semiautomatic rifle or any shotgun which is identical to any rifle or shotgun prohibited from importation under section 925 (d)(3) of this chapter as not being particularly suitable for or readily adaptable to sporting purposes except that this subsection shall not apply to—
(1) the assembly of any such rifle or shotgun for sale or distribution by a licensed manufacturer to the United States or any department or agency thereof or to any State or any department, agency, or political subdivision thereof; or
(2) the assembly of any such rifle or shotgun for the purposes of testing or experimentation authorized by the Attorney General.
26 U.S.C. 5822 Applies only to NFA (Machine Guns, etc) Weapons
Reference:
http://www4.law.cornell.edu/cfr/
27 CFR 478.39
§ 478.39 Assembly of semiautomatic rifles or shotguns.
(a) No person shall assemble a semiautomatic rifle or any shotgun using more than 10 of the imported parts listed in paragraph (c) of this section if the assembled firearm is prohibited from importation under section 925(d)(3) as not being particularly suitable for or readily adaptable to sporting purposes.
(b) The provisions of this section shall not apply to:
(1) The assembly of such rifle or shotgun for sale or distribution by a licensed manufacturer to the United States or any department or agency thereof or to any State or any department, agency, or political subdivision thereof; or
(2) The assembly of such rifle or shotgun for the purposes of testing or experimentation authorized by the Director under the provisions of §478.151; or
(3) The repair of any rifle or shotgun which had been imported into or assembled in the United States prior to November 30, 1990, or the replacement of any part of such firearm.
(c) For purposes of this section, the term imported parts are:
(1) Frames, receivers, receiver castings, forgings or stampings
(2) Barrels
(3) Barrel extensions
(4) Mounting blocks (trunions)
(5) Muzzle attachments
(6) Bolts
(7) Bolt carriers
(8) Operating rods
(9) Gas pistons
(10) Trigger housings
(11) Triggers
(12) Hammers
(13) Sears
(14) Disconnectors
(15) Buttstocks
(16) Pistol grips
(17) Forearms, handguards
(18) Magazine bodies
(19) Followers
(20) Floorplates
27 CFR 479.62 Applies only to NFA (Machine Guns, etc) Weapons
27 CFR 479.105 Applies only to NFA (Machine Guns, etc) Weapons
"It is well that war is so terrible -- lest we should grow too fond of it." Gen. R.E. Lee CSA
Skype ID: ACE1100