Thanks, Smart dog, I didn't realize they were being built so early. Let me rephrase that question, I have a pair of 16 ga. 31 inch barrels already breeched with patent breeches and I have a pair of Durs Egg locks. I want to make a fowling piece that would date about 1780-1790 as opposed to say after 1800. I know the patent breech was patented in 1787. There are many retailers that say their parts are "early" or "late" but they don't say how early or late, they just want to sell you what they have in stock. I want all the parts "correct" for a 1790 gun.....Looked for those books,,,,$300 for the pair,,,,OUCH!