It seems like I read somewhere (from Scott Sanchez, maybe?) that it was by pure accident that this fly came to be. Lynch used the copper wire as an underbody on some of his other nymphs for weight and mistakenly threw some of the unfinished flies in his fly box. He was having trouble getting his flies deep enough one day, tied on a copper wire wrapped hook to merely add weight to his tippet to get his “real” fly deeper, and caught a few nice fish on it. Thus, the Brassie was born.
True or not, it makes a good story!