I have a problem casting 500 gr. projectiles for my Pedersoli .45/70 Sharps Target rifle I use 1 to twenty alloy for casting bullets from an RCBS P/N 82085 Bullet Mould .45-500-BPS The bullets weigh in the range of 500 to 507 grs. Which while not bad for general plinking and hunting are way off for BPCR matches where the weight diffrence should be no more than .5 grains. But that's not my main concern, no, it's the fact that the majority of my castings are .0001 too large to fit easily into the brass cases and will not chamber into the rifle. Any suggestions?