Yes I am aware of that, which is why the sound of the barrels was so intriguing!

What I meant to ask.. were the" Ithaca Gun Co, Flues" models consistent in the design from the start until the end of the period, and then changes were made to create the "NID"? It seems to me that "Ithaca Gun Co" did make the "Flues" heavier as time went along, but I wasn't aware of other changes to the design of the model.