Welcome Cliff and neat Smith. Your regular frame Ideal was made in 1930 and unless marked otherwise on the barrel flats has 2 3/4" chambers.

It is possibly that a Research Letter might identify the original purchaser, who may have been a trap shooter
https://lcsca.clubexpress.com/content.aspx?page_id=22&club_id=43784&module_id=245742

Please look around the FAQs for lots more information
https://lcsca.clubexpress.com/content.aspx?page_id=274&club_id=43784

Any vintage double deserves a check and clean by a doublegun specialist smith before use, with an examination of the head of the stock for cracks and wall thickness measurement from breech to muzzle. Choke was not indicated on Smith guns so the smith will need to measure the constriction.