BV with crown = Birmingham blackpowder inspection mark 1904-1925
BP with crown = Birmingham definitive blackpowder proof 1904-
NP with crown = English Nitro proofmark in use starting 1904-1925
12/c in a dimond = Birmingham 12 bore with chamber shorter than 3" since 1877-1955
1 1/8 oz = Proofed for 1 1/8 oz shot since 1904-1925
13/1 bore size since 1925 = .719 to .729
Small crossed swords with letter S = I have never seen this nor can I find in in my reference material.
Narrows it down to after 1904 and before 1925. Alfred died in 1890 and the company lasted only 2 more years. I don't see how this gun could be made by A Lancaster and have proofmarks only from 1904-1025.
