teach me, i need to learn.....

have read several articles that hinted at the idea that the tippet/leader used when dry fly fishing should not float, seems to me if it sinks, it would pull the fly under or at least make it float funny....

sooooooo

my question(s)is A)should it float or not and B) how does one accopmlish the answer to part A of this question?

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one more cast and i'll leave......well maybe one just one more