Lead shot, as in buckshot, often has large variations in diameter.... I have some OOO Buck for my .357, and some balls roll/fall through the bore, while others are so large they cannot be forced into the breech without beating on the bolt, and then will not fire out, even at 3000 psi.... We're talking from about 0.350" to 0.362" diameter, all in one bottle of buckshot.... Bob