I know that there are folks who make this stuff for personal use. They heavily rely on the fact that they are not "engaged in the business of manufacturing explosive materials" because they don't sell, trade, or give it away, and thus are not engaged in "business", BUT they seem to stop short of actually reading ALL that applies.
Here is the law and the adjoining laws that combine...., and here is why this is not discussed here, and why I don't do this at home...
Title 18 USC on black powder making and possession
Title 18, United States Code, Sec. 1102, Chapter 40. Importation, Manufacture, Distribution and Storage of Explosive Materials
§ 841. Definitions
(d) Except for the purposes of subsections (d), (e), (f), (g), (h), (i), and (j) of section 844 of this title, “explosives” means any chemical compound mixture, or device, the primary or common purpose of which is to function by explosion; the term includes, but is not limited to, dynamite and other high explosives, black powder, pellet powder, initiating explosives, detonators, safety fuses, squibs, detonating cord, igniter cord, and igniters.
(h) “Manufacturer” means any person engaged in the business of manufacturing explosive materials for purposes of sale or distribution or for his own use
§ 842. Unlawful Acts (a) It shall be unlawful for any person—
(1) to engage in the business of importing, manufacturing, or dealing in explosive materials without a license issued under this chapter;
§845. Exceptions; Relief From Disabilities
(a) Except in the case of subsection (l), (m), (n), or (o) of section 842 and subsections (d), (e), (f), (g), (h), and (i) of section 844 of this title, this chapter shall not apply to:
(5) commercially manufactured black powder in quantities not to exceed fifty pounds, percussion caps, safety and pyrotechnic fuses, quills, quick and slow matches, and friction primers, intended to be used solely for sporting, recreational, or cultural purposes in antique firearms as defined in section 921(a)(16) of title 18 of the United States Code, or in antique devices as exempted from the term “destructive dev
So NOTE, "manufacture" includes making BP for personal use, even though it is prefaced by the phrase "..., in the business of...". There need not be any transactions for a person to be a "manufacturer" of BP, and BP is considered an "explosive" even though technically it deflagrates instead of detonating. So one needs a license to do this...., even for personal use.
NOTE that the Federal possession exemption is for fifty pound of black powder...commercially manufactured.... black powder. That means made by a licensed manufacture, NOT by a person making the stuff in the basement for personal use.
It is therefore NOT FAR FETCHED, that a Federal judge could easily find a person in violation of §845 above when in possession of a pound or less of home made black powder, and UNTIL somebody actually gets federally charged and taken to court..., we have NO WAY of knowing how a judge is going to rule.
So when people say this is "perfectly legal" they are actually predicting it will be thought as such if dragged into a federal court, but they don't actually KNOW that it's legal. OH and some folks will cite instances when persons have been charged and the charges have later been dropped... well that leaves no record nor does it impact the law and its application. It just means the particular AUSA handling prosecution decided it was not worth the time, at that time...
LD