My father is looking to sell his antique 12 ga W H Hamilton shotgun. The gun is in good condition with only minor pitting to metal. The wood is in very good shape. It fuctions perfectly. The only markings on it are a number 1233, and the marking Belgium Twist. About what is teh value
W.H. Hamilton, Belguim made Damascus Barrel, Low Base Shells....Sold in Hardware Stores and Thru Catalog Mail Order...from late 1800's and up to late 1930's...No Great Collector Value...$250.00 to $300.00 in the condition You discribe....
There were two "WH Hamilton" shotguns. From c.1875-1883 or so, there was an importer by that name located in New York City. The shotguns he imported were of Belgian origin and stamped as you describe. They were external hammer shotguns of average quality for the time. These are typical of the Belgian-made 'hardware catalog' shotguns sold by the hundreds of thousands if not millions throughout the country.
'WH Hamilton' surfaces again as a tradename on shotguns made in Belgium by Dumoulin in the early 1900's and marketed by Thomas Leary, another New York importer active from the mid-1890's through about 1904. These shotguns are also external hammer guns, and most I've seen have had some engraving on the locks.
The fact that yours has the numbering you describe leads me toward the latter production, so we can get pretty close in dating your shotgun from c.1900 and not be far off the mark. Although Dumoulin was making shotguns as late as 1930, I believe the WH Hamilton tradename was finished when Leary closed up in 1904.
As you read so often in posts regarding these old guns, it is absolutely NOT safe to shoot with any type of modern ammunition. I am very doubtful you will achieve the values listed in the above posts since collector interest is very limited (to oddballs like me). A very high condition specimen with quality engraving can bring those $$ figures but typical sale price on a typical piece tops out at $200.