Barrel historical resources are here
https://docs.google.com/document/d/1oPd3fOeToSHZwCaahXNIyV3sGVqow_Z_ENO8Fnk7kTQ/edit

and from Greener
https://docs.google.com/document/d/1f1ALnG5lwS9zCTlOuA064FSX6xeSEx-Nm2g1BaZyM5Y/edit

Gene: "In London the barrel-welding industry was never of great importance since 1844 no gun-barrel welder has practised in the Metropolis. The last maker was W. Fullard, of Clerkenwell, who enjoyed a high reputation for all kinds of sporting gun barrels."