I MAY have found the reason the medium burn powders were acting so goofy with the cast bullet....which still doesn't make sense to me as it's fine with the jacketed bullets unless the difference in bullet diameter mattered...which evidently it does. With the formed brass the bolt always hit a sticky spot at the mid-point of opening the bolt. It didn't matter if the cartridge had been fired and that hard spot was not present when the chamber was empty. I suspected the brass but even with spotting compound couldn't really see much interference. After dinking with this for about a week I finally decided to resize the brass in my 9 X 57 die then open the case neck back to 9.3 with just the expanding button in the 9.3 die. Problem solved. So...I fired a few rounds then full length sized them in the 9.3 die. Same issue arose. Seemed obvious to me the die was too long for the chamber. Ground a few thousandths off the bottom of the sizing die and all is well in Ozark land. Now to try some cast bullet loads with the medium burners!