It has the following proof markings:

"BP" beneath the crown, then the number "25", then another proof marking which I'm oiling out, another "25" and a last proof marking. Where can I find out what the proof markings mean? I've taken it to an antique gun dealer, and I'm thinking I'm going to have to go back to use his book. Is there an internet resource? I'm thinking that what I can do is write to the London Royal Historical Society if I can identify the gun, and get more information about it. They were sold to the confederates, correct? I also need to find information about the original owner, but the previous gun owner can't go to the cemetary until the weekend (she forgets her great-great grandfather's name, who was the original owner). Thanks!

Tim