151. Early William Malcolm Rifle Scope, circa 1855-1880. Rare 36" length, .65" tube diameter. Approximately 6-7 power. Clear optics- nice crosshairs. 95% original nickel. Moveable front mount will fit a 3/8th inch dovetail. Rear mount is 6.5" ahead of the eyepiece. Bottom of mount measures .586". Very rare scope for your antique target rifle. Antique.