Jamie, I have no knowledge of this pin either. I typed HCA into a search engine and got numerous posibilities. Could be a Manufacturers logo. I have yet to acquire the big book on enamel pins. It's on my want list.
* "OK, but, I was getting really good at not finding it." * ha ha myself included! Jamie,,What is the resource material that your friend is using that refers to it being Bulgarian and the number 250?
I'm surprised that there isn't their colors white/green/red, and or a lion,,a crown ,something relating to Bulgaria if its their party pin. .
My friend got this badge in a trade, this is the information that he was given from the other party. Any ideas about the cryllic letters ?
This is a scarce and extremely rare Bulgarian Royal times WWII National Socialist Movement Nazional Sozialistische NSDAP Bulgarian Party member badge / pin. There were only about 250 official members of this party in Bulgaria and badge is considered extremely rare. Nice black enamel work and cyrilic letters meanind N.S.D. During WWII Bulgaria was a NAZI German ally. Scarce militaria / military collector piece and one of the rare Bulgarian badges."
He's got some very interesting jewlery and Bulgarian items... Maybe shoot him an email and ask what is the source of this information he's listed for the pin... , G.