OK, I have just read the entirety of 18 U.S. Code Chapter 40.
I think we are OK.
https://www.law.cornell.edu/uscode/t...t-I/chapter-40
According to the law as linked,
You can store up to 50 pounds of commercial black powder for personal use.
https://www.law.cornell.edu/uscode/text/18/845
"(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 device” in section 921(a)(4) of title 18 of the United States Code;"
A manufacturer includes someone who makes it for his own use.
https://www.law.cornell.edu/uscode/text/18/841
"(h) “Manufacturer” means any person engaged in the business of manufacturing explosive materials for purposes of sale or distribution or for his own use."
But small arms ammunition and components thereof are excluded:
https://www.law.cornell.edu/uscode/text/18/845
"(4) small arms ammunition and components thereof;"
The passage I quoted earlier about black powder being excluded from the definition of ammunition applies to commerce of explosives Title 27 Part 555.11
This is important!
The Federal Explosives Law and Regulations book, (The "Orange Book"), covers Title 18, Chapter 40 and Title 27, Part 555!
https://www.atf.gov/explosives/docs/...54007/download
Title 40 is about the Importation, Manufacture, Distribution and Storage of Explosive Materials.
Title 72 is about Commerce in Explosives!
I had been searching the document for the term "Black Powder" and erroneously quoted the passage on ammunition and black powder from Title 72!
"Ammunition. Small arms ammunition or cartridge cases, primers, bullets, or smokeless propellants designed for use in small arms, including percussion caps, and 3/32 inch and other external burning pyrotechnic hobby fuses. The term does not include black powder."
This is about Commerce in Explosives!
Since we are not selling, I don't think Commerce in Explosives applies to us.
I think we are subject to Title 18, Chapter 40, and it excludes "small arms ammunition and components thereof".
So I think we are OK.