Overall length 51.25"; barrel length 36"; caliber .54. Markings: Type I-on lockplate forward of hammer "DERINGER/PHILA"; also known to exist with standard U.S. M1817 lock markings and barrel marks; Type II-on lockplate forward of hammer "US/DERINGER/PHILADELA" or "DERINGER/PHILADELA" and same on top of barrel. Although Type I rifle of this series appears at first glance to be a late contract rifle altered to percussion by means of the cone-in barrel method, in fact, it is an original percussion rifle made by Deringer from modified spare parts that remained after the completion of his 1840 contract. Type II rifle also evidences having been made from modified parts; however, its cone is set in an elongated bolster brazed to the right side of barrel. Speculation concerning these rifles is rampant; however, available evidence indicates that Deringer produced about 600 of these, most likely produced at the beginning of American Civil War.