We're going to need a lot more information to give you more than an educated guess-range.
The general rule, currently, is that Damascus-type (twist) type barrels are only suitable for "wall hangers" and should not be fired at all. Not with modern ammo and not with blackpowder (or equivalent) ammunition.
The thinking is that during the manufacture of the laminated steel there could have been small inclusions of slag that over the decades may have allowed corrosion to begin and that even though the gun has been safe in thousands of firings, maybe the next one will rupture the slowly growing defect.
That having been written, a "Best Quality" gun from Holland and Holland (or one of the other famous English makers) would probably still fetch $50,000 as a wall hanger.
So, the short answer to your question is: Somewhere between $20 and $100,000.
How much is a jc gubb London twist double barrel worth
About $200-250
I own a London Fine twist double barrel shotgun in fair condition, it was rated at $100.
50-100
1500
50-150 USD Circa 1900 Gold Hibbard doublebarrel mule eared Damascus finish shotgun. Made 1900
fine twist london
England, impossible to give value without name of maker.
The value of an old double barrel shotgun Damascus Bonehill Special BB London would actually be dependent upon a number of factors. Some of these factors would include the age exactly and the condition of the shotgun.
about 100-150 dollars..more or less
around $6000
The value of a WM Moore Co London laminated steel double shotgun depends on its condition. This gun in excellent condition is valued between 75.00 and 125.00 as of 2014.
The value of a London Fine Damascus 14 gauge double barrel shotgun marked JT Sang Ford depend on its condition. This gun in excellent condition is valued between 225.00 and 320.00 as of 2014.