Vig:

The B series guns are not part of the main numbering system and are primarily guns that were made for Gibbs by others. I would presume that a ball & shot piece would be from the first cycle of the B series which ended in 1910 at 5600. B3929 is from 1902. So maybe 1905-1906 for B4811?

Are there any other numbers on or around the fore-end loop, or maybe on the short rib? If you find a non-matching number there, that will be the maker's number (as opposed to Gibb's). Quite a few of these B prefix Gibbs guns are Webley products.
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