Flintlock Swivel-Breech Longrifle ca. 1830-40 David Boyer Based on his surviving work, Boyer seems to have specialized in swivel breech over-and-under rifles, like this example. A swivel breech mechanism has two barrels, placed one above the other, which are rotated manually, or swiveled, after each shot. The architecture of this rifle, especially the downward curving "Roman-nose" form of the buttstock, the style of the patch box, and other details of the decoration, relate closely to rifles made by members the Angstadt family in neighboring Berks County, suggesting that Boyer may have trained in their workshop, or another in that area, probably in the 1820s. Although Boyers known rifles are firmly rooted in the style of the early nineteenth century, he had a long career and is still recorded as a gunsmith in the federal census of 1870.. Flintlock Swivel-Breech Longrifle. American, Orwigsburg, Schuylkill County, Pennsylvania. ca. 1830-40. Steel, wood (curly maple, hickory), brass, sil