Mike, I've never seen a 12 ga. l.C. Smith with .717 bores that far back. Like I saidm this gun could have been special ordered with that tapered bore.
You highlighted (red) for both the right and left barrels. I formatted it with a distance between the right and left barrel. So the right column is right barrel, left column is left barrel.
It is very possible that the balls are sticking, and I will send the gage back to them. I had called them not long ago asking if they could make a longer rod to go deeper, 16" would be great but one of the workers said they aren't doing that as of yet.
