Hi Yip,
Let's look at some data. Of 25 single barreled fowling guns built by John Twigg between 1766 and 1790, only 4 had barrels longer than 43 inches. All of those were large bored guns built to hunt waterfowl by shooting them on the water from fairly long range and one of them had a 72" barrel. Of the other 21 guns, only 4 had barrels 40"-43" and the rest were <40". Of course, these guns are all of English style and a couple were shortened during their working lives. My original English fowler from the 1760s or early 1770s has a 39" barrel. During the 18th century, Spanish barrels were considered the finest smoothbored barrels in the world. The typical length of those barrels was 42". Very long fowler barrels were common during the 17th and early 18th centuries partly because of slow burning powder. After the improvements to powder (and producing good round bird shot) later in the 18th century, largely made by the French chemist Lavoisier, there was no need for long barrels because the powder burned up completely in barrels as short as 32". Large bored long barreled waterfowl guns persisted into the 19th century but the barrels on most other bird guns were reduced to lengths between 32 and 39". I agree that a long barrel on a fowler is elegant and certainly can produce a good shooter fir birds but consider this, the only way it looks good is if you make the forestock very slim and of almost egg shell thickness. If you don't, that long barreled gun will look like some clunky punt gun. A thicker stock on a shorter barreled gun does not look quite as bad.
dave
