G'day Curl,
this was one of the questions I put to the seller, but alas its one of those rifles that went through proof but for whatever reason didn't get stamped with its bore size. My little 360 Henry is in the same boat, wonderful quality but not punched with anything to indicate its cal. I can't get away to have a look at it for about a week so I might send an email off to Dicksons. They have been very helpful in the past. Also, the barrels seem to be steel, not damascus.

underlever