Kevin;
Lack of a chamber marking would I believe date it to prior to 1887. The Crown/BP is the provisional proof (Temporary), Crossed Scepters with V is the view mark & Crossed Scepters with BPC is for the definitive proof (Final). These are Birmingham marks & of course are all Black Powder proofs. The 13 for the bore size would indicate it accepted at time of proof a plug gauge of .710" in dia, but would not accept one of .729". These marks were all in use for a long period so about all I can say with certainty is it would certainly seem to pre-date 1887. It would in fact appear to be slightly older than my ML'r.
