The following weapons are regulated under the National Firearms Act (NFA):

1. A shotgun having a barrel or barrels of less than 18 inches in length;
2. A weapon made from a shotgun if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 18 inches in length;
3. A rifle having a barrel or barrels of less than 16 inches in length;
4. A weapon made from a rifle if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length;
5. Any other weapon, as defined in subsection (e);
6. A machinegun;
7. Any silencer (as defined in section 921 of title 18, United States Code); and
8. A destructive device.

[26 U.S.C. 5845; 27 CFR 479.11]