Can you tell me about my Lincoln Jeffries shotgun?

The left barrel is engraved ?Winner of Gold Medal London?, and the right with ?Winner of 20 Guinea Prize for Choke Bores London?.

The serial number is 4096 and the barrel flats are marked ?BV? and ?BP? and stamped ?nitro-proof?, ?2.3⁄4 chambers? and ?1.1⁄4oz load?.

The action is non-ejector and is either a boxlock with sideplates or a sidelock.

SHOTGUNS
Bill Harriman
Lincoln Jeffries (1847? 1932) was a prominent Birmingham gunmaker best known for designing the tap loading underlever air rifle subsequently built by BSA.

He occupied various premises in Whittall Street and Steelhouse Lane in the heart of the city?s gun quarter.

Less memorably, he was also involved in litigation with William Ford over a patent, and was forced to concede that Ford had bored his guns that won a gold medal in The Field trials of 1879.

Jeffries was something of an inventor, with a dozen patents to his name.

Though he was a gunmaker in the true sense of the word, your gun will have passed through many pairs of hands, as he would have had the specialised functions of manufacture performed by outworkers.

The inscriptions on the barrels refer to prizes won in The Field trials of 1875 and 1879.

The original proof marks are for blackpowder from the 1904 Rules of Proof, which were in use until 1954.

However, from the description of the gun, it is most likely that it was made before World War I because the shot charge was reduced to 1.1⁄16oz in 1915 to save on lead.