I don't know which act it was but I don't think it was in 1913 but for some reason 1922 comes to mind and I'll have to research it a bit, but here is some info on the mark of the "country of origin" for the U.S. of A.:
Oct. 3, 1913, ch. 16, Sec. IV, F, subsecs. 1 and 2, 38 Stat. 194
Act of September 21st, 1922, ch. 356, title IV, Section 592, 42 Stat. 982(it may not be the 1922 Tariff Act) Section 592 -
http://books.google.com/books?id=m1orAAA...iff+Act+of+1922Looks like the country of origin clause is in Section 304, but I can't find a text that I can access. "Tariff Act of September list, 1922 (DHA 1922, pp. 854, 918), Section 304
(2). — All imported goods and their wrappers must bear marks of origin..."
section 304, Tariff Act of 1930-
http://thomas.loc.gov/cgi-bin/cpquery/?&...=TOC_63700& The stamp "Made in Germany" is going to take it out of the Prussian category.
"Crown" over "U"(inspected, maybe 2nd proof) and "Crown" over "S"(smoothbore) are typical. The date stamp is not in a typical location, but then again it is of German origin. Are there any initials just ahead of the flats near the lower rib?
Kind Regards,
Raimey
rse