This just in from the NSSF (National Shooting Sports Foundation):
Open Letter From The Bureau of Alcohol, Tobacco, Firearms and Explosives
The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) on June 30 provided an open letter to all federal explosives licensees/permittees concerning the black powder exemption under the federal laws. As a service to the industry and our members, NSSF is forwarding this letter from the Firearms and Explosives Industry section chief that outlines the conditions applicable to the exemption. View the letter here:
https://www.atf.gov/sites/default/files/assets/Explosives/Industry/open-letter-black-powder.pdf

Wayne

BTW, due to the 2nd to last paragraph discussion manufacturing of BP in any quantity, I doubt it's a good ideal to discuss home manufacturing in an open forum, or, for that matter, any online medium.

Wayne

Searching the ATF site further I found an older ATF Newsletter on the same subject making it clear that individuals manufacturing black powder for their own personal non-business do not need a license.
http://www.atf.gov/files/publications/newsletters/fel/fel-newsletter-2011-06.pdf

For some reason this was not included in the recent open letter. Hopefully it was an oversight.

Wayne