CHeck the barrel, butt and breech.
when did spring make 12g single barrel shotgun serial number 30368
Do you mean a hammerless single-shot, double-barrel, slide-action...? email@example.com
E designates 1953
i got a 12 gauge king nitro double barrel double triggers and double hammers no serial number on it
Your serial number indicates that you have a Ithaca crass model double,that was made in 1903.
It sounds to me that you have a Ithaca Flues model double barrel shotgun.With the serial number that you provided,your shotgun was made by Ithaca in 1917.
With the serial number that you provided,your Ithaca double barrel shotgun with the damascus barrels was produced in the year 1900.
probably 30/06 unless the barrel was changed.............