Anybody know where I can find a definitive list of proof marks? I'm trying to date a pistol and I'm not recognizing a lot of the marks on this one, it's a "belgian" nagant in some 9mm caliber I was sold it on the understanding that it had the pre 1893 belgian marks and was dated 1878. my importer recived it today and says neither of these marks are present. ( he also describes a series of marks I've never heard of) so any tips on where to find this stuff would be helpful