Traffer,
It is explained pretty well in this article that you need the FFL 06 license to sell ammunition or the components to make ammunition, as well as being part of ITAR:
You can read for yourself here:
https://johnpierceesq.com/do-i-need-...-cast-bullets/
Here is the applicable US Codes ( Law):
Manufacturing Ammunition & Licensing according to the US Code:
https://www.law.cornell.edu/uscode/text/18/923
Definition of what Ammunition is according to the US Code:(a) No person shall engage in the business of importing, manufacturing, or dealing in firearms, or importing or manufacturing ammunition, until he has filed an application with and received a license to do so from the Attorney General. The application shall be in such form and contain only that information necessary to determine eligibility for licensing as the Attorney General shall by regulation prescribe and shall include a photograph and fingerprints of the applicant. Each applicant shall pay a fee for obtaining such a license, a separate fee being required for each place in which the applicant is to do business, as follows:
(1) If the applicant is a manufacturer—
(A) of destructive devices, ammunition for destructive devices or armor piercing ammunition, a fee of $1,000 per year;
(B) of firearms other than destructive devices, a fee of $50 per year; or
(C) of ammunition for firearms, other than ammunition for destructive devices or armor piercing ammunition, a fee of $10 per year.
https://www.law.cornell.edu/uscode/text/18/921
Applicable ITAR info:(17)
(A) The term “ammunition” means ammunition or cartridge cases, primers, bullets, or propellent powder designed for use in any firearm.
http://www.law.cornell.edu/cfr/text/...I/subchapter-M
ITAR stands for the International Traffic in Arms Regulations which were promulgated to implement the provisions of the Arms Export Control Act of 1976 (AECA). The relevant section (emphasis added) is as follows:
Any person who engages in the United States in the business of either manufacturing or exporting defense articles or furnishing defense services is required to register with the Directorate of Defense Trade Controls. For the purpose of this subchapter, engaging in the business of manufacturing or exporting defense articles or furnishing defense services requires only one occasion of manufacturing or exporting a defense article or furnishing a defense service. Manufacturers who do not engage in exporting must nevertheless register.
As for what constitutes ‘defense articles’, 22 CFR 121.1 contains a complete listing under what is known as The United States Munitions List (USML). The relevant section is contained in Category III of the list in subsection f:
(1) The components, parts, accessories and attachments controlled in this category include, but are not limited to cartridge cases, powder bags (or other propellant charges), bullets, jackets, cores, shells (excluding shotgun shells), projectiles (including canister rounds and submunitions therefor), boosters, firing components therefor, primers, and other detonating devices for the defense articles controlled in this category.
The short answer is that, those licensed to manufacture and sell cast bullets are also required to register for ITAR and pay the registration fee.