I totally disagree with your statement that the lightest straight barrel for a given caliber and length is lighter in weight and handles better than a swamped barrel. You implied that handling disadvantage of a swamped barrel with your statement to "take the magical balance and weight claims with a bit of salt." Sounds to me like you don't have and perhaps have never carried, shouldered, or shot a longrifle with a swamped barrel.
I have both, a .50-cal. Traditions Pennsylvania Longrifle with a straight barrel that I bought in ~2004 and an Early Lancaster rifle with a swamped barrel that I bought in ~2006 or '07. The Traditions longrifle has a 40¼" long straight barrel with a 1:66" twist. My Early Lancaster has a 44½" swamped barrel with a 1:56" twist. Overall length of the Traditions PA Longrifle is 56". My Early Lancaster rifle is 60¼" in length. My Early Lancaster rifle is about 2-lbs lighter than my Traditions Longrifle even though it is more than 4" longer than the Tradition's Longrifle. The swamped barrel, even though it is 4¼" longer than the 40¼" barrel on the Traditions rifle, balances beautifully right where my left hand grasps the forearm. It is far easier to carry, mount, swing, and hold on target than the Traditions with the straight barrel that is nose heavy to carry mount, swing, and hold on target.. If I were ordering a new longrifle and I could either upgrade the wood in the stock for for more grain or upgrade from a straight (or straight tapered) barrel up to a swamped barrel I absolutely would go with the swamped barrel every time. It is a real pleasure to use.
