One last question, are you weighing each charge or using a powder measure? If extruded powders settle differently inside the case, it could definitely change how much the case is filled by the powder, this causing the crunching you’re experiencing on some of the rounds. Using a long drop tube and dumping the powder in the case the same way every time can help with this problem. If using a powder measure, your charge weights can vary up to .5 grain with varget, in my experience.


JTD