Ok, honestly. Hell if I know. It happened about 25 years ago in late May on the Niangua above Bennett, second day of a two day float trip where it rained about two inches the first night. Obviously a big rise. I was fishing a big aluminum lip crawdaddy crankbait, maybe a Bomber or something? I guessed the fish at about 6 pounds. So what would that measure? I do not have a clue. But it was a big fish, by far the largest smallmouth I've ever caught before or since.