The National Firearms Act (NFA) contains no minimum age in regard to the possession of NFA firearms. Regardless, federal firearms law prohibits a licensed importer, manufacturer, dealer or collector (i.e., licensees) from selling or delivering any firearm or ammunition to any individual that the federal licensee knows or has reasonable cause to believe is less than 18 years of age. Federal firearms law further provides that a licensee shall not sell or deliver any firearm or ammunition that is other than a shotgun or rifle or ammunition for a shotgun or rifle to any individual that the federal licensee knows or has reasonable cause to believe is less than 21 years of age.

[27 CFR § 478.99(b)]