Ross, when you partial size does your entire case neck get reduced? In my experience, no. So, in some of my rifles, if I continue to shorten the distance between the shell holder and the die, the case head space actually lengthens and will not fit into my chamber at all. I tested this using the RCBS micrometer. The fired case measured zero, then full length resizing to where shell holder just made contact to die lengthened the case anywhere from 2-4 thousandths, and those cases will not chamber. It was only after I overcammed, per RCBS instructions, did my shoulders start bumping back 1-2 thousandths and would fit.