Imported distilled spirits in bulk containers may, under the provisions of this subpart, be withdrawn by the proprietor of a distilled spirits plant from customs custody and transferred in such bulk containers or by pipeline to the bonded premises of his plant, without payment of the internal revenue tax imposed on imported spirits by 26 U.S.C. 5001. Imported spirits so withdrawn and transferred to a distilled spirits plant (a) may be redistilled or denatured only if of 185 degrees or more of proof, and (b) may be withdrawn from internal revenue bond for any purpose authorized by 26 U.S.C. chapter 51, in the same manner as domestic distilled spirits. Imported distilled spirits transferred from customs custody to the bonded premises of a distilled spirits plant under the provisions of this subpart shall be received and stored thereat, and withdrawn or transferred therefrom, subject to the applicable provisions of 27 CFR part 19. However, distilled spirits plant proprietors are not required to file application on TTB Form 5100.16 to receive imported spirits from customs custody. The person operating the bonded premises of the distilled spirits plant to which imported spirits are transferred shall become liable for the tax on distilled spirits withdrawn from customs custody under 26 U.S.C. 5232, upon release of the spirits from customs custody, and the importer shall thereupon be relieved of his liability for such tax.