I have seen Ubertis vary from .427 to .430, original Winchesters from .426 to .429, and Malins, new and old from .428 to .431!" My remedy is to load .428s, and they shoot well in no matter what .44-40 I shoot. Even when I have given rounds to others at matches, they work for them. My Rossi 92 in .44-40 LOVES the .428s, shooting clover leafs at 25 yards.