This is an early Third Model version of Parry W. Porter's distinctive turret rifles (approximately 680-1225 serial number range) and includes the U-shaped turret cover, a piece missing from most surviving Porter rifles. It has off-set blade and notch sights, "ADDRESS/P.W. PORTER/NEW-YORK" and "P.W. PORTER'S/PATENT/1851." on the upper left barrel flat, "O" on the outside of the hinged side plate below the hammer, matching serial numbers on various components, and smooth stock with crescent buttplate.