It would be interesting to see comparative figures from Rocketman's POI meter for the Darne, Dickson, a well made sidelock, a stubby modern boxlock and the Baby Bretton. All with equal barrel and stock lengths if possible. I mention the Bretton since its major mass, the receiver, is compact and near the trigger hand like most boxlocks, while it has light aluminum barrels and a hollow stock.
I do not read Powell's comment as a denial of the physics at all. He is saying that the distribution of the gun's major mass, the action, between the hands affects its handling. He is always referring to the distribution of that particular mass, the action, not the weight of the whole gun. Powell is talking from the point of view of the craftsman who has to make good handling guns to make a living, which he did.
