I have to agree that it appears to be cast.perhaps a fantasy coin depicting the style of b.c.celtic design.similar types are sold at viking faires.I'm no expert but I am also unable to find a known example of real coin to match.an acis test kit would be a wise and cheap investment.
good luck,let us know
edit...I didnt notice the age of original post.the fact that op never returned to discuss metalurgy or verification tells me all I need to know.