Only an estimated 250 of these revolvers were manufactured around the early 1860s before production was halted in 1863 due to infringement of the Rollin White patent. Some appear to have been assembled in/after 1869 when the White patent expired. These were among the first large caliber metallic cartridge handguns manufactured in the U.S. and were the only large caliber metallic cartridge handguns available during the Civil War aside from pinfire revolvers. The matching serial number is on the cylinder pin, front of the cylinder, loading gate, front strap, and grips. It also features a triangular blade front sight, "ALLEN & WHEELOCK. WORCESTER. MS. U.S./ALLEN'S PAT'S. SEPT.7. NOV. 9. 1858." on the left side of the barrel, an ejector mechanism that uses the trigger guard as the operating lever, a raised notch rear sight at the rear of the frame, and smooth grips. The ejector mechanism is updated from Allen's prior trigger guard operated loading lever for percussion revolvers.

Very good with traces of original blue finish in the protected areas, mottled gray and brown patina on most of the balance, some light pitting/oxidation, oil staining, and mild overall wear. The grips are fine with strong original finish, minor scratches, lower edge wear, and a number of hammering marks on the butt. Mechanically fine.