There is probably little to be gained, in the way of accuracy, by replacing the press. Dies and measuring tools are another matter. Typical, one piece, FL dies over size cases' necks, so that when the expander ball is pulled back through, there is so much pull on the case that it yields slightly at the shoulder, and since it does not do this evenly, necks are cocked. When bullets are seated in these cocked necks the result is crooked ammunition, to a degree that is detrimental to accuracy. Really good dies that do not excessively reduce the case's body diamater, and in the case of unturned necks, leave only a little work for the expander ball, are the key. This sort of FL die, combined with the best of seaters will result in the straightest ammunition. Beyond this using cases that are from the same lot, that have been fired and sized approximately the same number of times, and that have a minimum of body and neck thickness runout is a great help. Do you have a Sinclair International catalog? It is available online.
