To determine the age of a Victor ejector shotgun made by Crescent Firearms Co. with serial number 858-304, you would typically need to reference specific production records or a serial number database for Crescent Firearms, which ceased operations in the early 1930s. Many Crescent shotguns were produced in the 1920s, so it is likely that your shotgun dates from that era. For a more precise date, consulting a firearm expert or collector's guide that specializes in Crescent firearms could provide additional insights.