The value of an Iver Johnson 20 gauge double barrel shotgun, such as the one with serial number 76786, can vary based on factors like its condition, age, and any unique features. Generally, these shotguns can range from $200 to $1,000 or more. For an accurate appraisal, it's best to consult a firearms expert or a reputable auction house specializing in vintage firearms.
With the serial number that you provided,your Ithaca double barrel shotgun with the damascus barrels was produced in the year 1900.
Your Iver Johnson double barrel shotgun can be dated by the words hammer forged.This places production from 1936-1941.these were well made mass produced field grade shotguns of high quality.
1896
27p
Exactly how is the shotgun marked (all markings), and double-check the serial number. sales@countrygunsmith.net
1900
If it is a double, remove barrel and you will see it along with serial #.
about 200.00
it is worth about 400 dollars
Around July of 1925
Impossible to answer without more information.
That is impossible to determine without knowing the manufacturer and model of the shotgun.