"The hazmat fee on caps and black powder (as well as smokeless powder and primers) is not a "Government Fee", it is a surcharge imposed by UPS or FedEx that simply contributes to directly to their respective bottom lines (less the cost of the sticker they put on the box, of course). The only "Government" involvement is the classification of the aforementioned items a "hazardous materials"(along with a host of other things) by the Government via the CFR 49 statutes published by the Department of Transportation."
I was under the impression that it was regulated and fees were imposed by the Dept of Transportation, and or, the National Transportation Safety Board. Nonetheless, thanks for further piquing my interest on the subject. Not that I doubt what you say, but just out of curiosity, I will delve deeper into the issue and see what, if anything, that I can come up with.