I hope, the Off-Topic area is the right place for this:

Several Bulgarian re-enactors, including me, were recently invited to participate in an event in Moscow, Russia at the end of June.
As we plan to drive all the route from Bulgaria to Moscow, we have to pass through Romania, Moldova, Ukraine & Russia. None of us has any knowledge and experience with law of these countries, so we need to know at least basic regulations in these countries.

Could some of the forum-mates, living there, give us any useful information, regarding their law-regulations - requirements for weapons, armours, tranzit and so.

Any answer will be highly appreciated.
Thanks in advance!

Last year we went to Sigishoara, Romania with all the weapons we have - blunt and sharp and we had no problems. There is a certain Medka you can ask about this...

I would advise against bringing sharpened weapons into Russia and Ukraine, there should be no problems with blunts. Do not forget to ask the organizers of the event to send a message to the border crossing point you will be using beforehand - they did that for our group two years ago and we had no trouble at all since border guards already knew who we are and where we are going. Organizers should be able to arrange for visas to be made "for cultural visit" so they would be free.