Originally Posted By: Tamid


I measured bore diameter and right was .615 and left .610. Would it be common to have different bore diameters on the same gun? I have an Ithaca chart that indicates bore diameter for 20ga should be .615.



Polishing would not explain a .610 bore diameter if standard is supposed to be .615. .610 is tighter than that, not more open. That's maybe a little more difference from one bore to the other than you would expect, but it's not unusual to find a few thousandths difference in bore diameter.