27 CFR §70.321

1. (a)Persons required to register. Every person engaged in a trade or business in respect of which a special tax is imposed by one of the following sections of the Internal Revenue Code is required to register with the Alcohol and Tobacco Tax and Trade Bureau.
   1. (1)-(5) [Reserved]
   2. (6)Section 5731 (relating to special tax on manufacturers of tobacco products, manufacturers of cigarette papers and tubes, and export warehouse proprietors); or
   3. (7)Section 5802 (relating to importers, manufacturers and dealers of National Firearms Act weapons).
2. (b)Procedure for registration. The registration required of a person by reason of the person being engaged in a trade or business, in respect of which one of the special taxes listed in paragraph (a) of this section is imposed, shall be accomplished by timely executing and filing, in accordance with the instructions relating thereto, TTB Form 5630.5, Special Tax Registration and Return.