"
Game Guns & Rifles", Richard Akehurst:
For instance it was not possible, at an economic cost, for London makers to forge their own twist barrels; W. Fullerd, of Clerkenwell, was the last in London who specialised and excelled in the art, carrying on the unequal struggle until his death in 1833.
....
William Fullerd of Compton Street, Clerkenwell and Charles Lancaster of Tichfield street...supplied leading gunmakers, such as John and Joseph Manton and, in his early years as a gunmaker, James Purdey.
After this the trade moves to Birmingham. He also Lancaster as finisher who would purchase the tubes from Birmingham, bore and file them and sell them to the London trade. Fullerd would produce the barrels from start to finish.
Akehurst describes and names the type of steel used to make twist barrels. From best to worse: 'Stub Damascus', 'herring-bone', 'Threepenny skelp', 'Twopenny skelp' or 'Wednesbury skelp' and finally 'Sham damn skelp'.
Pete
