I have recently acquired a Swedish Rolling Block which has been rechambered to 50-70 Govt. I have 25 brass cases from starline and a Lee mold 515-450. My barrell is clean and free of leading. I have slugged my bore twice with a result of .512. The cast boolits from the Lee mold drop at .515 to .516. I am wondering if these are to big as is or need to be sized? I loaded up a dummy round and tried chambering it iny Rifle and had no issues. It chambered easily at the max overall length.