While perusing another site I ran across a comment about how moving the shoulder back a couple of thousandths gives all "the benefit of full length sizing." Now I am fully aware that semi-auto & pump actions, need full length sizing to prevent chambering and extraction problems, but other than that what is the benefit? If the OAL for the case is within specs, and the OD dimensions of the neck are OK is there anything to be gained from moving the shoulder back even a couple of thousandths after it has been fire formed to fit the chamber? I have never had a problem with a neck sized case failing to chamber or chambering hard (I've been rolling my own since 1971), but I have experienced shorter case life with the full length resized cartridges for my 760 carbine, and I don't load these very hot compared to my other 06's. My groups almost always tighten up a little when I'm not using virgin brass in bolt actions and the Encore.
Have I gotten it wrong all these years in believing that after firing a belted mag cartridge it will head space on the shoulder if you only neck size it, and that will help lengthen case life by slowing the stretching and thinning of the brass just in front of the belt? (After neck sizing I always use a Lee OAL guage and trimmer and usually I don't have to remove much, if any, material) I know that .002 isn't much but to quote Father Guido Salducci, "It all adds up." Why work your brass any more than absolutely necessary, and what is absolutely necessary?