This used Union Arms Co.(Toledo, OH) 2-7 shotgun fires the 2.5" black powder 12 gauge shells. It has a 28" Damascus barrel with 2.5" chamber. This shotgun was manufactured between 1907 and 1917. In 1907, the Union Arms Co. redesigned their slide by shielding it behind a steel plate that covered the rear half of the opening. This shotgun has that plate. This shotgun has a double trigger. The front trigger cocks and decocks an internal firing pin and the back trigger fires the gun. In 1917 the Union Arms co. was absorbed by Ithaca Gun company.