We have to keep them 20 years and then we can toss them.
You can not legally build an AR without paperwork. You must fill it out for the serial #part (the lower or receiver).
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Can you show me the law that says this? This is what I found on the ATF website page 5 questions 9.
https://www.atf.gov/file/61721/download
9. May I lawfully make a firearm for my own personal use, provided it is not being made forresale?
Firearms may be lawfully made by persons who do not hold a manufacturer’s license under the GCAprovided they are not for sale or distribution and the maker is not prohibited from receiving orpossessing firearms. However, a person is prohibited from assembling a non-sporting semiautomaticrifle or shotgun from 10 or more imported parts, as set forth in regulations in 27 C.F.R. 478.39. Inaddition, the making of an NFA firearm requires a tax payment and advance approval by ATF. Anapplication to make a machinegun will not be approved unless documentation is submitted showingthat the firearm is being made for the official use of a Federal, State, or local government agency (18U.S.C. § 922(o),(r); 26 U.S.C. § 5822; 27 C.F.R. §§ 478.39, 479.62, and 479.105).