Looks like J.G. Riga tried to also dance with the port appraiser:
http://books.google.com/books?id=9Xs4AAAAIAAJ&pg=PA783&dq=U.S.+vs.+riga+on+barrels&lr= .

And there was some exception to the law/rule for scattergun tubes in the 1890 tariffs(See "Court & Treasury Decisions" on the lower portion of the page):
http://books.google.com/books?id=M1UrAAA...barrels&lr=

Kind Regards,

Raimey
rse