49 CFR 173.170 - Black powder for small arms.
Black powder for small arms that has been classed in Division 1.1 may be re classed as a Division 4.1 material, for domestic transportation by motor vehicle, rail freight, and cargo vessel only, subject to the following conditions:
(b) The total quantity of black powder in one transport vehicle or freight container may not exceed 45.4 kg (100 pounds) net mass. No more than four freight containers may be on board one cargo vessel;
(c) The black powder must be packed in inner metal or heavy wall conductive plastic receptacles not over 454 g (16 ounces) net capacity each, with no more than 25 cans in one outer UN 4G fiberboard box. The inner packagings must be arranged and protected so as to prevent simultaneous ignition of the contents. The complete package must be of the same type which has been examined as required in § 173.56;
(d) Each completed package must be marked “BLACK POWDER FOR SMALL ARMS” and “NA 0027”; and