The pre WW1 Parker order books are full of 20 gauge guns made for 3" shells. Some are on heavy frames, some are not. Edwin Hedderly's famous Parker long barrel smallbore wildfowl guns are on light frames. I owned a 20 gauge original 3" gun serial number 153,333 that was ordered at 8 pounds. It was a great gun and I would like to have it back.