Iam the proud inheritor of my grandfather's shotgun, which I have used myself when hunting with him many years back. I have had the gun cleaned and inspected by a local gunsmith, but was left with some questions. This is a hammerless, double barrel Damascus steel barrel shotgun, serial number 7680 and labeled specifically as: -FOREHAND- under which is labeled: HOPKINS & ALLEN ARMS CO. and under that: NORWICH, CT U.S.A. There are no other marks, but for the "patent pend" barely visible inside, when the gun is broken open, opposite the serial #. I suspect that years ago we shot this gun with incorrect "modern" smokeless powder shells. I understand this gun is not to be shot with plastic casing smokeless powder shells and is to be shot, if at all, with black powder shells. If this is correct advice, what guage shell did this gun take and where can I get the shells? If they need to be hand made, who makes them? Any help is much appreciated.