A 5 weight would be okay for Puget sound Chinook, smile. Can't realy say that with any real experience but out here I don't even call it a KING unless it is over 30#. I just don't know if there is enough backbone to even tire out a 40#+ Chinook. But then again I haven't caught one on it so who knows.
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Taking my fishing poles with me to a body of water that has fish in it is not an excuse to enjoy the scenery.