Biggest largemouth I ever had a chance to weigh was just over seven pounds. Have caught several in the 22+ inch range (not on the Mississippi). My brother caught one 15 years ago on a small lake in west central Wisconsin that tipped the scales at 8 lbs 10 oz. That was after laying dead in a cooler all day after a fishing trip. Biggest smallie I’ve ever caught was 6lbs 3 oz. 22.5 inches. Once again not on the river though.