Manufactured from 1857 to 1861. Blade front and notch rear sights, with the Kerr's Patent marking on the loading lever, the Mass. Arms address on the top strap and "ADAMS.PATENT/MAY 8th 1853" on the left side of the frame. Equipped with a sliding safety, single letter proofs on several parts and circled cartouches on both sides of the one piece grips with a brass grommeted lanyard hole in the center.