I have a tool that moves the roller table in very precise increments for fine tuning the beat error. I only used it on one caliber I used to do for a small manufacturer, it's not terribly practical for everyday use. It has a table with a collet in the center that clamps on the roller table, then a finger clamp that holds the balance rim. The table turns around the collet, with index marks so you know how far you went. You can very easily turn the roller table a fraction of a degree, and then go