A similar shotgun from the same range, serial number 6478 from c. 1814, is pictured on page 33 of "The Mantons: Gunmakers" by Neal and Back and has the same unusual waterproofing/water draining system employed on this shotgun. This distinctive shotgun is not listed in either that book nor the supplement. The elevated and slightly concave rib at the breech is has angled slots on each side that funnel water down through a cavity an out a slot through the trigger guard finial. The frizzens also have fences to direct water away from the pans, and the pans are guttered to direct water away from the powder as well. Its an interesting and rather complex solution to the known difficulty of keeping flintlocks functional in wet weather which is especially prevalent in the British Isles. The rib also has a small front sight and some engraving at the breech and is signed "Joseph Manton's NEW Improvements by His MAJESTY'S PATENT." The flat bevelled locks are signed "JOSEPH MANTON-/LONDON" and have engraving on the borders and stepped tails. The upper tang and most of the furniture is also engraved. The stock has a smooth forend, blank wrist escutcheon, checkered and rather slender wrist, and a 14 1/2 inch length of pull. Matching serial numbers are on the barrels, breeches, and lower tang. The case has a Joseph Manton trade label inside, an added plaque on the front of the lid, and contains a leather shot snake, Sykes powder flasks, three-piece rod, attachment, and spare flints.