A couple of comments on this great rifle/shotgun combo: The style of the proof marks are definitely pre-1887 as the only indication of caliber is the '39' gauge mark. Also, since the action shows an Anson & Deeley patent use number that would date it to within 14 years after 1874. The odd thing, to me anyway, is the thickness of the rifle chamber walls; they are much thicker than the typical .500 BPE's I've seen and in combination with the Webley Screw Grip third fastener it makes for one very strong rifle.