I found out.
It has been unlawful since 1934 (The National Firearms Act) for civilians to own machine guns without special permission from the U.S. Treasury Department. Machine guns are subject to a $200 tax every time their ownership changes from one federally registered owner to another, and each new weapon is subject to a manufacturing tax when it is made, and it must be registered with the Bureau of Alcohol Tobacco and Firearms (BATF) in its National Firearms Registry.
To become a registered owner, a complete FBI background investigation is conducted, checking for any criminal history or tendencies toward violence, and an application must be submitted to the BATF including two sets of fingerprints, a recent photo, a sworn affidavit that transfer of the NFA firearm is of "reasonable necessity," and that sale to and possession of the weapon by the applicant "would be consistent with public safety." The application form also requires the signature of a chief law enforcement officer with jurisdiction in the applicant's residence.
Since the Firearms Owners' Protection Act of May 19, 1986, ownership of newly manufactured machine guns has been prohibited to civilians. Machine guns which were manufactured prior to the Act's passage are regulated under the National Firearms Act, but those manufactured after the ban cannot ordinarily be sold to or owned by civilians.
I did find a FN MFG. NEW IN BOX M249 5.56mm BELT FED MACHINE GUN (SAW) NIB "PRE 86 DEALER SAMPLE" for sale.
