Here is what the inscription translates to approximately. It is in Hungarian. "Kirner, Pest, Kirner Josef of Pest, Royal Court Armourer. It is likely a royal gun from the Austrian Hungarian empire.
Here is another example.
http://www.msgunowners.com/t22145-joseph-kirner-shotgun-help

Here is an approximate value if you have an acount. This gun was made for Franz Josef I.
http://www.artfact.com/auction-lot/hahn-doppelflinte,-josef-kirner-budapest-aus-de-1-c-0c90384348
Nice find very cool gun!