NFA

The National Firearms Act is the US federal law that places a separate layer of regulation on certain firearms and accessories considered to need extra oversight. Among the categories it covers are the silencer, the SBR, short-barreled shotguns, and machine guns, each of which must be registered and approved before it changes hands. Approval comes with a tax stamp, the documented proof that the required federal transfer tax has been paid.

For the precision shooter this matters most when adding a suppressor to a rifle, since that path runs through the NFA process regardless of barrel length. A rifle built with an integral suppressor is regulated the same way, because the law looks at the suppressing device itself rather than how it is attached. Compliance is a paperwork and waiting-period exercise, not a barrier to ownership where these items are legal.