0.729" is the "Mathematical" Standard derived from the weight of the round lead ball which would fit the bore. I do not believe there has ever been a time in the history of gunmaking that the makers have exactly followed that standard. There has always been variations due both to manufacturing tolerances as well as the makers idiosyncrasies. Many of the older guns such as the above mentioned Bakers & Lefevers were I believe intentionally over-bored with the idea they would most likely be used with thin wall brass shells using over sized wadding.
