There are multiple sites that are dedicated to the Mosin-Nagant rifle.  Do a search and you'll find them.  You will also be able to find how to trace the origins of the rifle (makes, dates, units, etc).  I found all kinds of info for both my Finnish and Russian Mosin-Nagants.  I dont have the sites linked, but they are out there for sure.  Ditto for Enfields, Mausers, Arisakas, Carcanos, Garands, etc.