You won't find them.
Hansen Cartridge Co operated in the late 80s and early 90s, as the US importer and marketer of the imported brand now known as "Prvi Partizan," and made in one of the current countries that made up the former Yugoslavia. Hansen ammo had the headstamp "nny" which is Cyrillic for "PPU." When civil war tore apart Yugoslavia in 92 or 93, Hansen could get no product and went under. The PPU factory rebuilt after the war and now manufactures ammo under the Prvi Partizan brand name, with the same "nny" headstamp as before.
Noah