I have a RCBS .30-180 FN which throws to approximately .310, and with my first cast load in that caliber gave me 1 3/8” at fifty yards. I will have to deal with the powder charge as I noticed the groups improved as I raised the barrel between shots. 22 grains SR 4759 is the minimum recommended charge for the Lyman 170-grain .30-30 bullet and so I thought would be a safe place to start with the RCBS. The bullet, sized through a .311 Star die with gas check, is seated to be flush with the base of the neck and not protrude into the powder space, with two lube grooves showing out the top. The rifle is a Remington 700, and I use an RCBS two die set with a LEE universal expander to flare the case mouths. The problem is that the expander ball in the RCBS die mikes to only .307” (for jacketed bullets)and I am seating .310” diameter cast bullets. How could I get a .309” expander ball for the case? Are there any custom makers for this? I would get an entire die to put it in, along with a neck-sizing die as well. I'm having a similar issue with my .45 Colt. The dies are universal RCBS .45 ACP/AR/Colt which make the case too narrow for the Colt. Does anyone make custom internal parts for these dies. I assume I will have to get separate Colt dies as well, but I am not sure who to see.
Bisley